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                     PREPARING GRAIN FOR STORAGE
                             VOLUME I OF
                       SMALL FARM GRAIN STORAGE
                      CARL LINDBLAD, PEACE CORPS
                         LAUREL DRUBEN, VITA
PROGRAM & TRAINING JOURNAL                 ASSISTANCE           
                                        MANUAL SERIES NUMBER 35E
                   FIRST PRINTING    SEPTEMBER 1976
                   SECOND PRINTING,
                   IN THREE VOLUMES    JULY 1977
                   THIRD PRINTING      JULY 1980
                 1600 Wilson Boulevard, Suite 500
                   Arlington, Virginia 22209 USA
              Tel:  703/276-1800 * Fax:   703/243-1865
                        TABLE OF CONTENTS
     The Purpose of the Manual
     The People Who Prepared This Manual
     How To Use This Manual
SECTION 1:  THE GRAIN STORAGE PROBLEM                                      
     Good Grain Storage Is Important to Farmers
     Grain Is a Living Thing
     What Happens to Grain in Storage
     Good Grain Storage Depends Upon Better Drying and Better Storing
     "Good Grain Storage Helps Farmers"
SECTION 2:  GRAIN IS A LIVING THING                                     
     Characteristics of Grain and How They Affect Storage
     "Grain Is a Living Thing"
SECTION 3:  GRAIN, MOISTURE, AND AIR                     
      What Moisture Is
      Moisture in Grain
      Moisture in the Air
      How Air, Moisture, and Grain Interact
      Safe Moisture Levels in Grain
      Movement of Moisture in Stored Grain
      Where You Are Now
SECTION 4:  PREPARING GRAIN FOR STORAGE                                
      Harvesting and Threshing
      The Need for Drying
      How Drying Happens
      Safe Drying Temperatures
      Testing Grain for Moisture Content
      "Preparing Grain for Storage"
SECTION 5:  GRAIN DRYER MODELS                                  
      Sun Drying Using Plastic Sheets
      The Improved Maize Drying and Storage Crib
      Newer Drying Methods
      A Simple Oil Barrel Dryer
      Instructions for Using the Oil Barrel Dryers
      The Pit Oil Barrel Dryer
      Philippines Rice Dryer
      Solar Dryers:  Part 1:   Construction
      Part 2:   Operating Instructions
APPENDIX A:  Different Ways to Present Grain Storage                 
APPENDIX B:  Information on Moisture Meters                          
APPENDIX C:  Working Paper on the Volunteer Role in Grain          
             Storage:  "Problems Related to Popularizing New
             Farm-level Grain Storage Technology"
APPENDIX D:  Bibliography:  Reprint of Listings Prepared by           
             the Tropical Products Institute, London
CONVERSION TABLES                                                       
                      PURPOSE OF THE MANUAL
Small Farm Grain Storage is a set of how-to manuals.   Together these
volumes provide a comprehensive overview of storage problems and
considerations as they relate to the small farmer.   The authors
recommend the volumes be purchased as a set because the material forms
an excellent and complete working and teaching tool for development
workers in the field.  This grain storage information can be adapted
easily to meet on-the-job needs; it has already been used as the
basis for a grain storage workshop and seminar in East Africa.
This set of publications retains the purpose of the original volume:
to bring together and to communicate effectively to field personnel
1) the basic principles of grain storage and 2) the practical solutions
currently being used and tested around the world to combat
grain storage problems.  Only the format has been changed to:
 *   reduce printing and postage costs.
 *   permit updating and revising one volume at a time.
 *   provide smaller books that are easier to hold and use
    than the large, single volume.
 *   make portions of the information available to the user
    who is especially interested in only one or another of
    the major aspects of small farm grain storage.
Of course, it is impossible to cover all storage situations in this
manual.  But farmers who understand the basic, unchanging principles
of drying and storing grain are better able to adapt ideas, suggestions,
and technologies from other parts of the world to their own needs.
This material was prepared for use by those who work to facilitate
such understanding.
Volume I, "Preparing Grain for Storage," discusses grain storage
problems as they are faced by small-scale farmers.   This volume
contains explanations of the structure of grain, the relationship
between grain and moisture, the need for proper drying.   One large
section contains detailed, fully illustrated plans for constructing
a variety of small-scale grain dryers.
Volume II, "Enemies of Stored Grain," is an in-depth study of two
major enemies:  insects and rodents.  Each is discussed in detail
with guidelines for 1) defining the size of the problem and 2) protecting
grain by both chemical and non-chemical means.   This volume
includes dose and use information for a variety of pesticides, as well
as suggestions for preparing materials to be used in audio-visual
Volume III, "Storage Methods," contains a survey of storage facilities
from the most traditional basket-type granary to metal bins and cement
silos.  The emphasis in this volume is on improving existing facilities;
for example, there are detailed construction procedures for an
improved mud silo.  Storage in underground pits and sacks also is
discussed.  There are guidelines for using insecticides in storage
situations.  The largest silo presented in detail is the 4.5 ton
cement stave silo.
Carl Lindblad served as a Peace Corps Volunteer in Dahomey (Benin)
from 1972 to 1975.  As a Volunteer, Lindblad worked in programs
designed to introduce and popularize a variety of grain storage
technologies.  Upon his return to the United States, he began the task
of pulling together this manual as a consultant to VITA and Peace
Corps.  At present, he serves as a consultant to a number of international
organizations, specializing in appropriate technologies for
grain storage -- in the areas of planning, extension and evaluation.
He spends much of his time in the field.
Laurel Druben served as an International Voluntary Services, Inc.
Volunteer in Laos from 1966 to 1968.   While in Laos she was a
curriculum planner and a teacher of English as a second language.
Subsequently, she worked with a consulting firm evaluating government-funded
research and development projects, ran a small education-oriented
business, and was a free-lance consultant and proposal
writer.  Druben, who has worked and lived in India and Micronesia,
as well as Southeast Asia, is Director of Communications for VITA.
Many thanks are due to the skilled and concerned people who worked to
make this manual possible:
    A number of VITA people provided technical review, artwork,
    and production skills:
    Staff assistance -- John Goodell
    Section 4, Vol. I materials -- Frederick Bueche
    Technical review -- Douglas Barnes, Merle Esmay, Henry Highland,
                                Larry Van Fossen, Harold Willson, Kenton Harris
    Artwork -- George Clark, John Goodell, Kenneth Lloyd,
                       Nicholas Reinhardt, Guy Welch
    Thanks are extended to the following individuals and institutions
    that provided invaluable assistance in early stages of work on
    the manual:
     Mary Ernsberger and Margot Aronson, Peace Corps Program and
        Training Journal, USA
    Brenda Gates, Peace Corps Information Collection & Exchange, USA
    Tropical Stored Products Center, TPI, Great Britain
    Henry Barre and Floyd Herum, Agricultural Engineering Department,
        Ohio State University, USA
    Department of Grain Science and Industry, Kansas State University,
    Agricultural Research Service, Department of Agriculture, USA
    Extension Project Implementation Department, Ministry of
        Agriculture, Ethiopia
    F. W. Bennett, Midwest Research Institute, USA
    Supervised Agricultural Credit Programs (SACP), Belize
    Peter Giles, Nicaragua
    Donald Pfalser, Agricultural Cooperatives Development International
        (ACDI), USA
    Technical Assistance Bureau, US Agency for International
        Development (AID), USA
    International Development Research Center, University of Alberta,
    League for International Food Education (LIFE), USA
    Institut de Recherches Agronomiques Tropicales et des Cultures
        Vivrieres (IRAT), France
    Post-Harvest Crop Protection Project, University of Hawaii, USA
    Agricultural Engineering Service, FAO
    African Rural Storage Center, IITA, Nigeria
    Institute for Agricultural Research, Ahmadu Bello University,
    Swaziland Rural Grain Storage Project
    Jim McDowell, Food Technology and Nutrition Section, UNICEF, Kenya
    Gordon Yadcuik, Centre Nationale de Recherches Agronomiques (CNRA),
    R. A. Boxall, Indian Grain Storage Institute, A.P., India
    Siribonse Boon-Long, Ministry of Agriculture and Cooperation,
    Asian Institute of Technology, Chulalongkorn University, Thailand
    Merrick Lockwood, Bangladesh Agricultural Research Council
    International Rice Research Institute (IRRI), Philippines
    Dante de Padua, University of Los Banos, Philippines
Small Farm Grain Storage is part of a series of publications combining
Peace Corps practical field experience with VITA technical expertise
in areas in which development workers have special difficulties
finding useful resource materials.
ACTION/Peace Corps
Since 1961 Peace Corps Volunteers have worked at the grassroots level
in countries around the world in program areas such as agriculture,
public health, and education.   Before beginning their two-year
assignments, Volunteers are given training in cross-cultural, technical,
and language skills.  This training helps them to live and work
closely with the people of their host countries.   It helps them, too,
to approach development problems with new ideas that make use of
locally available resources and are appropriate to the local cultures.
Recently Peace Corps established an Information Collection and
Exchange, so that these ideas developed during service in the field
could be made available to the wide range of development workers who
might find them useful.  Materials from the field are now being
collected, reviewed, and classified in the Information Collection and
Exchange system.  The most useful materials will be shared with the
development world.  The Information Collection and Exchange provides
an important source of field-based research materials for the production
of how-to manuals such as Small Farm Grain Storage.
VITA people are specialists who volunteer their free time to answer
requests for technical assistance.   Many VITA Volunteers have lived
and worked in other countries, often as Peace Corps Volunteers.  Most
VITA people now work in the United States and other developed
countries where they are engineers, doctors, scientists, farmers,
architects, writers, artists, and so on.   But they continue to work
with people in other countries through VITA.   VITA Volunteers have
been providing technical assistance to the Third World for almost
20 years.
Requests for assistance come to VITA from many nations.   Each request
is handled by a Volunteer with the right skills.   For example, a
question about grain storage in Latin America might be handled by a
professor of agriculture, and a request for an improved planting
implement would go to an agricultural engineer.   These VITA Volunteers,
many of whom have lived and worked in Third World countries, are
familiar with the special problems of these areas and are able to give
useful, and appropriate, answers.
VITA makes the expertise of VITA people available to a wide audience
through its publications program.
                        HOW TO USE THIS MANUAL
Development workers can use material from this manual in a number of
     *    Discussions.   The manual provides clear presentations of grain
         storage principles from which you can take material to lead
         discussions with farmers and village leaders.
     *    Demonstrations.   There are suggestions for demonstrations and
         experiments which you might find helpful to illustrate grain
         storage principles to farmers.
     *    Leaflets.  Some of the material has been prepared in the form
         of illustrated leaflets which can be used directly by you
         with a farmer.  They may require little or no adaptation by
         you.   But, if you prefer, you can use the structure of the
         leaflet and substitute photographs specific to your area.
         The material on rodent control in Volume II is a good example
         of this kind of leaflet.
     *    Construction Plans.   Many of the construction plans have been
         simplified so that you will be able to work more closely with
         the farmer.  Some of the plans are fully illustrated.  You
         could add photographs of the work steps showing conditions in
         your area.  It is likely that after you introduce the material,
         farmers can follow the instructions themselves.  The
         plans are written so that they would be easy to translate
         into local languages.  The Improved Maize Drying Crib in
         Volume I is a good example of a step-by-step, illustrated
     *    Checklists.   Some of the material most likely to be useful for
         small-scale farmers has been simplified and prepared in checklist
         or hand-out form.  This material would lend itself to
         illustrations or photographs, so it can better fit into the
         local situation.  The checklists on controlling grain storage
         insect pests included in Volume II are in this category.
     *    Examples.  The appendices contain examples of leaflets that
         have been prepared by development workers in several countries.
         These examples have been included to give you some
         idea of how the materials in this manual might be organized,
         illustrated, translated, and presented to reach farmers.
     *    Sources.  Wherever possible, addresses are given so that you
         can write for more information on a subject.
     *    Further Information.   Other appendices contain information on
         areas which, although important, cannot be covered fully within
         the scope of this manual, for example, storage program
         planning.  A bibliography is provided at the end of each volume.
These are some of the aims of Small Farm Grain Storage.   You will
probably find added uses.  While it is not possible to make this
manual specific to the situations or culture of your particular area,
the information is presented so that you can do this very easily by
making additions or substitutions to the material.
Dimensions are given in metric units in the text and illustrations.
Conversion tables are provided at the end of each volume.
This manual will grow and change as its readers and users send in
additional material, comments, and ideas for new approaches to grain
storage problems and better ways to communicate with farmers.  Your
own ideas and conclusions are welcome.   A form has been included for
your comments.  Please send us the results of your silo or dryer
building.  Let us know how you used the information and how it could
be make even more useful to you.   Tell us how you changed a plan to
fit local needs.
Your experience will help us to produce manuals of growing usefulness
to the world-wide development community.
For your convenience, a reply form has been inserted here.  Please
send it in and let us know how the manual has helped or can be made
more helpful.  If the reply form is missing from your book, just put
your comments, suggestions, descriptions of problems, etc., on a
piece of paper and send them to:
                         GRAIN STORAGE
                         3706 RHODE ISLAND AVENUE
                         MT. RAINIER, MD  20822
                  1 THE GRAIN STORAGE PROBLEM
Farmers all over the world lose much of
their grain after it is harvested.   Farmers
work hard to plant and grow crops.   And
often they do not receive good returns
for their time and effort.  The grain is
attacked in the field and in storage by
insects, rodents, birds, and other pests.
The grain that pests do not eat, they
dirty with their droppings and their bodies.
Farmers have lived with these problems
for hundreds of years.  So they have
developed ways to deal with them.
Many old ways are wasteful, but a
number of the old methods are good
and must be kept until they can be
replaced or improved.
In recent years, however, the grain
storage problem has changed (and, in
some cases, temporarily worsened) as
steps toward full development have
been taken.  For example, now there
are new seed varieties which grow faster
and yield more grain.  Farmers plant these
new seeds, and this grain is ready for
harvesting earlier than it used to be.
This grain is ready to be harvested during
the rainy season.  The farmer has always
dried his crops in the sun, but there may
be little sun during this season.   Also,
it is likely this new variety of grain must
not be left to dry in the field:   if this
grain dries too long in the field, it will
shatter (break).  But if the farmer brings
the grain from the field and stores it
before bringing the moisture content of
the grain down to 13% or lower, the grain
will rot and mold.

51ap01.gif (393x393)

The farmer must find a way to dry his grain,
store it safely, and plant another crop -- all
in the time he used to spend on one crop.
His many old methods must be changed to help
with new problems.

51ap02.gif (317x317)

The Problem
The basic question then is how to help farmers protect their grain from
attack.  The answer must be to give the farmer enough information about
harvesting, drying, storing, insects, rodents, and molds so that he can
fight the problems successfully.   No one can find answers to problems
without having enough information about the subject.
Farmers need to know that there are steps they can take to protect their
own grain.  Perhaps a farmer can save significant quantities of grain
by making a simple change in the way he is doing things now.  Perhaps
there is another way of drying or of storing which fits into his situation
well.  A farmer needs to be presented with ideas that can be demonstrated,
that make sense to him, and that fit into his life easily.  This is done
by supplying technology and help which is appropriate.   With this kind
of help, change for the better is more likely to take place.
The following chapters offer many ideas about the grain storage problem.
The materials have been prepared to make them easy for you to use
in your work.  The manual should help you get information to those
who can use it.
When people in universities and government agencies talk about storage,
they are discussing a serious subject.   They talk about such facts as
     *   approximately 30% of grain in storage all over the world is
        being lost because of insects, rodents, and molds.
     *   improving grain storage would mean less hunger, improved
        nutrition for the individual, and a higher standard of living
        and a sounder economy for the nation.
     *   quality grain for international trade is of increasing importance.
     *   improper storage of grain leads to weight loss, monetary
        loss, seed loss, quality loss, food loss.
These concerns are real.  And there is a definite need for people to
deal with grain storage questions at this level.   Many new ideas and
plans result from the testing, thinking, and planning being done all
over the world by scientists, teachers, and researchers.
But when small farmers talk about grain storage problems, they are
talking about their livelihood.   And there are some very important
reasons why grain storage questions are of concern to them.
Food for the Family
Grain is very likely the single most important
thing eaten by the farmer and his family.
Whether it is maize, wheat, rice, millet, or
sorghum, it is important for his family.   The
farmer may not think about grain losses and
use words like quality and quantity.   But he
can see that insects, rodents, and molds ruin
a lot of his grain, and that there is not as
much for his family to eat.  He can taste
the difference between clean grain and grain
which has been damaged by mold.   Farmers feel
the loss of grain and the need for better
storage when they run out of grain for food
before the next harvest.  Then they must use
what little money they have to buy food.   Or
they must borrow against the next crop and
start out in debt.

51ap03a.gif (230x230)

Another food loss is harder to measure.   But it is real.   Some insects
eat out the best parts of the grain.   These are the parts which contain
the vitamins and minerals which make grain the healthy food it is.  The
farmer may not see this loss.   But he should be told about it.  Lack of
nutritious food can lead to sickness and more problems.
Seed for Planting
Part of the harvested grain is the seed for the
next crop.  The farmer must let the seeds rest
in a cool, dry place before he plants them.
Poor storage of seed grain means that some of
the seeds, or many of them, will not germinate
(grow) when they are planted.   If the seeds are
not stored well, the farmer will have to plant
many extra seeds to get enough plants.   Often
seed grains that have not been stored well do
not grow well:  they may grow at different speeds.
This causes problems with cultivating and harvesting
the grain.

51ap03b.gif (256x256)

Money to Fill Needs
A farmer usually must buy some of the tools and equipment he needs for
home and farm use.  He may need to purchase corrugated metal sheets for
building, metal pots for cooking, metal tools for farming, or cloth for
making clothes.  To get items which he cannot make himself, the farmer
has to offer money, or he has to barter.   Most farmers sell the grain they
do not use for food or seed to get money.   Or they trade the grain for
the things they need.

51ap04.gif (230x230)

Because of poor drying and storage facilities, farmers cannot keep their
grain safely for any period of time.   They are forced to sell the grain
soon after harvest.  The prices are low at this time because no one needs
grain.  Everyone is harvesting, and there is plenty of grain available.
Until the farmer can dry and store his grain safely, he is not going to
grow much more than he needs for his family.   This lack of safe storage
means that total production of grain remains low.
Most farmers will not think in terms of country-wide production.  But
they will have in mind some things they would like to do if they had
more money.  Good grain storage can lead to more food, more money, better
seed, and a better future.
Grain has certain characteristics which farmers must understand if they
are to be able to dry and store their grain well.   Here are some of the
characteristics of grain which will be discussed:
     *   Growth of seed grain.
     *   Protection of the kernel by the seed coat.
     *   Respiration (breathing) of grain kernels.
     *   Moisture (water) in grain kernels.
     *   Moisture movement between grain and air.
Farmers know a lot about planting and growing grain.   But most farmers
will not think about grain in all the ways listed above.  If they do
become aware of these characteristics of grain, the reasons for good
grain storage are going to make a lot more sense to them.  And farmers
are going to be able to do more toward solving their own problems.
Keeping grain safe in storage depends upon a number of things.
Moisture, temperature, insects, and molds, for example, all can cause
changes in grain put into storage.   All factors which are most important
to good grain storage are presented in the following paragraphs;
some are discussed in greater detail in other places in the manual.
REMEMBER:  All of the following points are related to one another.

51ap05.gif (230x486)

Insects and their part in grain storage are the subject of another section
It is an important section.  Insects eat and ruin a lot of grain.  Because
they grow inside the grain kernels, some insects are not found in grain
until after they have done a lot of damage.   The section on insects will
give information on the major grain storage insects, on where to look for
them, and on how to control them.
Insect activity, and the damage which results from this activity, is
closely related to temperature and moisture in stored grain.  It only take
a few insects in the right conditions -- for example, in warm , moist
grain -- to make enough moisture and heat so that large numbers of insects
can grow.  More insects will make more heat and water, and so on.   They
create the right conditions for the growth of molds.
Molds are very small plants.   They are so small they cannot be seen on
grain, but they are always there on the grain kernels.   In warm, moist
grain, they will germinate (grow) and produce threads called
hyphae.  These hyphae push through the seed coats of grain kernels and
attack the embryos of the grains.   Molds cause damage in a number of ways
     *   They produce chemicals called enzymes which can stop seeds
        from germinating and growing into new plants.
     *   They decrease the quality of the grain for food and for
     *   Some molds produce chemicals which can poison people.
Farmers certainly are familiar with the sight and smell of grain damaged
by mold.  But they are probably not aware of the conditions that lead to
molding, and they may not know what they can do to protect their grain
from mold.  Helpful information and suggestions are presented later.
Moisture Content (Wetness)
Drying grain, and keeping it dry in storage, is the most important part
of good storage.  Many problems of grain storage are caused by moisture.
Both grain and air have moisture, and they act together in ways that are
important to understand.  Therefore, a following section discusses
moisture content in grain and in the air; it also explains how moisture
in grain and moisture in the air are important to each other.

51ap06a.gif (130x600)

There are two temperatures which are important.   One is the outside
temperature of the air; the other is the temperature of the air and grain
in the storage place.
It is easier to store grain in areas where the air temperature is low or
never gets too hot.  In very cold weather, insects and molds do not grow
very quickly, or at all.  Seeds do not breathe as much.
In warm places, the grain is warm when it is put into storage.  Then, as
the outside temperatures go up, the temperature in stored grain is likely
to get even higher.  When the temperature in the grain goes up, certain
things start happening:
     *   Insects start growing and breeding.
     *   Mold spores start multiplying.
     *   Molds, insects, and grains all live and breathe faster,
        causing heat, water, and carbon dioxide to increase in
        the stored grain.
Even in this brief look at temperature, it is easy to see the need for
keeping grain cool and dry.  Keeping storage containers protected from
the hot sun is important.  Farmers who understand this fact have discovered
an important grain storage principle.
Rats and mice eat a lot of grain.   They can eat the whole kernels of
grain sorghum, wheat, and millet.   They chew on ears of maize.
Rodent damage is the easiest kind of
damage to see.  Yet farmers may not
realize how much damage rodents can
do; they may not be aware that rodents
spread diseases.  Or they may not know
what they can do to stop rodents from
eating their stored grain.  The section on rodents gives information
on the habits of rodents, the signs of rodents that a farmer should
look for, and some ideas for keeping rodents out of stored grain.

51ap06b.gif (317x317)

Clean Grain and Clean Storage Places
Farmers often do not realize how important it is to clean the place for
storing grain.  Even grain that is healthy and whole when put into
storage can be damaged by insects or ruined by molds if stored incorrectly.
Farmers need to know that good grain storage requires planning for a good
storage container or place, and careful handling and cleaning of the grain.

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Many farmers can improve the condition of
their stored grain simply by cleaning and
repairing their present grain storage
containers and buildings, and by putting
only healthy grain into storage.   This
manual helps spell out the necessary
steps for farmers who wish to improve,
(1) the quality of the grain they store,
and (2) the container into which they put
the grain.
Improved Drying
As mentioned before, drying is the key to storing grain safely.  The
section on "Preparing Grain for Storage" covers the importance of
careful harvesting, threshing, and moisture measurement before putting
the grain into storage.  "Grain Dryer Models" presents plans for a
number of grain drying methods.
Improved Storing
The manual section on storage
discusses methods already being
used by farmers, and gives ideas
for improving these methods.   Also,
the section provides plans and
construction procedures for a number
of grain bins.  Each of the
storage methods is presented in
terms of its possible advantages
and disadvantages for use by farmers.

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Your Role
You will have to decide how to use the materials in this manual.  Some
farmers may be ready to make a mud silo; others require information on
good storage practices for storing grain in sacks.   One village may be
ready to make an oil barrel dryer.   Another village might like to try
solar dryers.  These are decisions which you and the farmers in your
area must make together.  The purpose here simply is to provide information
upon which good decisions can be made, and to provide some basic guidelines
in important grain storage areas.
The following leaflet provides an illustrated look at what good grain
storage can do for farmers.
Suggested Uses:  This is a script which could be used to alert farmer
                 to the need for improved storage.  Choose the points
                 you feel are most important and have them translated
                  and illustrated as necessary.
     *   A good crop of grain means plenty of food.
     *   Farmers work hard to grow their grain.   Grain is important.
     *   A good crop means seed for planting the next crop.
     *   A good crop means you can buy things for your family and
     *   But you must have a good place to keep your grain after the
        harvest.   You cannot use all the grain right away.
     *   It is not good to sell grain right after harvest.  The
        price for grain is lower at harvest time because more
        grain is available than at other times of the year.
     *   You cannot eat all the grain.   You will want some later.
     *   Seed grain must be stored safely until planting time.
     *   A good grain storage place is a place to keep grain safe
        until you want to sell it, to eat it, or to plant it.
     *   There are many ways to store grain.   Some farmers store
        grain in sacks.  Some farmers store grain in clay jars
        and in the rafters of their homes.  Some farmers store
        grain in special buildings.
     *   All grain storage places must protect the grain from
        insects, mice, rats, and other pests.
     *   Rats and mice enter open grain storage places easily.
        They can eat and spoil a lot of grain every day.
     *   Birds and chickens like to eat grain too.
     *   Many insects attack stored grain.
     *   Insects get into grain very easily.   Some of them can fly,
        and some begin eating the grain in the field before harvest.
     *   Insects lay many eggs.   These insects eat and spoil a lot of
        your grain.
     *   Insects, rats, and mice eat so much grain that soon there is
        less for you to sell and eat.
     *  Insects and rats put the droppings from their bodies on the
        grain while they are eating.  This makes the grain dirty.
        You cannot make as much money when you sell this grain.
     *   People get sick from eating grain which rats and insects
        have put droppings on.
     *   Molds also attack stored grain.
     *   Molds are tiny plants.   You cannot see these plants.
        Mold plants float in the air and need warmth and
        moisture to grow.  Mold plants usually are on stored
        grain even though you cannot see them.
     *   Molds give grain a bad smell and change the color of
        the grain.
     *   Molds like to grow in warm, wet storage places, so you
        must keep grain cool and dry.
     *   People can get sick if they eat grain with mold on it.
     *   It is important to keep insects, rats, molds, and other
        dangers away from your stored grain.  Good grain storage
        means more money and more food.
     *   Your extension worker can help you with grain storage problems.
        He knows how you can fight insects, rats
        dangers.   He will have ideas on ways you can improve your
        grain storage.
The following pictures show how one artist has chosen to present the
subject, "Good Grain Storage Helps Farmers."   As you can see, he has
chosen a certain number of important ideas from the scripts and
highlighted them using pictures.   Perhaps these pictures will provide
you with ideas for illustrating your own leaflets.

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                   GRAIN IS A LIVING THING
The Structure of Grain
Grain kernels are living things.  Grain which will be used for seed must
be kept alive.   Living seeds also store better.
Maize, rice, sorghum, wheat, millet, and so on, are all cereal grains
which belong to the same grain family.  As you know, these grains do not
look alike.   Maize is a large kernel with a triangular shape; it has a
hard coat and a large, oily germ which is easy to see on one end of the
kernel.   Sorghum, on the other hand, is a round seed in a brittle or
leathery seed coat.  The germ is very hard to see.
Although they look different, the grains all share three basic parts:
the seed coat; the endosperm; the embryo (germ).

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The Seed Coat
     *  Surrounds the embryo and the endosperm.
     *  Protects the grain from attack by certain insects if
        it is dry and un-cracked.
     *  Cannot keep out molds and some insects.  Those insects
        which attack the embryo are most dangerous because the
        seed coat at the embryo is weak.
The Endosperm
     *  Takes up the largest part of the seed.  It is 80% of
        the kernel volume in most grains.
     *  Is the seed's food storage place.  It is mostly starch
        and protein.
     *  Provides food for the developing seed when planted and
        food for the seed in storage.
     *  Provides food for farmers and others if the seed is not
The Embryo
     *  Is the part of the seed which can develop into a new plant.
     *  Contains most of the protein, fat, and vitamins of the
     *  Is attacked easily by some insects and by molds.   Seed
        grain which is attacked will not grow into strong plants
        or will not grow at all.   Food grains without embryos do
        not provide as much nutrition as grains with embryos.
Healthy grain can be kept in storage longer than grain which is broken.
The threshing methods used by farmers often damage many of the grains.
If the grain is to be threshed before it is stored, the threshing must
be done very carefully.  Careful handling of the grains helps the grain
protect itself from danger.  Here are examples of ways in which healthy
grains are protected by their structures:
                   *   The husks on maize ears protect the grain from
                      damage during harvesting and drying.
                   *   The husks on rice kernels protect that grain
                      from attack by most insects.
                   *   A hard, dry seed coat with no cracks or splits in
                      it prevents molds and insects from getting into
                      the kernel easily.
                   *   The endosperm of dry grain is hard and is not as
                      easily attacked by insects.

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Stored rice or wheat or maize, etc., act in one way or another because
each has certain characteristics which are affected by the ways it is
stored.   A farmer should know the characteristics of the particular
grain he is storing.
Because there are many kinds of grain, this manual can not talk a lot
about each.   Here it is most important to point out that the structure
of the grain (the way it is made) plays an important part in what does
or does not happen to that grain in storage.  The structure of the grain
affects the length of time the grain can be stored and the kind of
storage container it should be put into.  You may want to prepare materials
for the farmers in your area which talk directly about the structures
of the grains they grow and which storage containers are best for their
Grain breathes.   Each kernel gets oxygen
from the air and burns food from its
endosperm.   This process gives off heat and
and carbon dioxide.  This process in grain
is called respiration.  Respiration is faster
or slower depending upon the temperature and moisture in the grain.
Respiration is slow when grain is cool and dry.  There is only enough
respiration to keep the embryo of the grain alive.  This process can continue
in storage for a long time if the embryo is not attacked by mold,
insects, or high temperatures.  Slow respiration is important for storage.
Growth does not happen at this low respiration level, but seed life

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If the stored grain has too much moisture or heat in it, the grain begins
to respire faster.  When seed grain is planted, for example, it germinates
(grows) because respiration has been speeded by water in the ground and the
warmth of the soil.

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The way that grain, moisture, and temperature work together is important
for farmers to understand.  Grain put into storage with a lot of moisture
in it breathes much faster than dry grain does.  This moist grain makes
more heat and creates conditions leading to mold growth and insect
attack.   The farmer who understands this will see the need for storing
cool, dry grain.
Heat Producing and Heat Holding
Grain produces heat during respiration.  If
the grain is cool and dry, it respires very
slowly and the amount of heat it makes is
very small.   But if respiration gets faster
for some reason, grain makes more and more
heat.   Spots of hot air form inside the storage
container because the stored grains hold the

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The temperature outside the storage container does not have an immediate
effect on the grain in large silos, but it can be a problem for the
farmer who has a small metal storage bin which stands by his front door
and faces the sun for some hours each day.  The heat from the sun warms
the bin, and this warming spreads to the grain inside.  Any insects and
molds present in the grain will grow much more quickly.
All harvested grain holds a certain amount of
moisture.   Most of the moisture is inside the
kernel; if the grain is very wet, some of the
moisture is around the outside of the kernel.
Farmers must dry the grain until it only
holds about 12-13% moisture if they are to
store grain safely.  Since moisture and drying are so important, they are
discussed more fully in another section.

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Grain has other characteristics, such as flow and pressure.  These are
subjects not particularly important to a small-scale farmer.   Mainly he
needs to know what the grain looks like inside and what there is about
grain that makes it act in certain ways in storage.
                  GRAIN IS A LIVING THING
Suggested Uses:   Select points as needed.   Translate and illustrate
                 them for distribution to farmers in your area.
     *  Each kernel of grain is a living thing.  Each grain is a
     *  A seed can grow into a new plant just like the one it came
     *  Most of the seed is food around a tiny part of the seed
        called the embryo.   Some people call the embryo the germ
        of the seed.
     *  This embryo is the part of the seed that will grow into a
        new plant.
     *  One part of the embryo will form the shoot that grows
        above the ground.
     *  The other part of the embryo will grow and become the
        root of the plant.   This is the part of the plant that
        grows under the ground.
     *  There is a seed coat around the food and embryo.   This coat
        protects the grain from being hurt.  Careful harvesting,
        threshing, and storing will protect the seed coat.
     *  While they rest, seeds breathe and use the food that is
        inside them.
     *  Seeds stay alive and are good for planting and selling if they
        rest in places which are cool and dry.
     *  A good grain storage place must be cool and dry.   It must protect
        the grain from insects and other dangers.
     *  Do not use high heat to dry the grain you are saving to plant
        with.  High heat will kill the embryo.
     *  Store your seed grain separately from the grain you plan to
        sell or to use for food.
     *  Check the grain often.  Make sure it is dry.  Do not let it
        get too warm.   Make sure there are no insects in it.   Smell
        it to see if molds are present.
     *  Good storage of your seed crop means the next crop will be a
        good crop.   The living grain will grow into a new plant when
        you put it into the earth.

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                       GRAIN, MOISTURE, AND AIR
Moisture is water or wetness.  But moisture is a better word to use when
talking about grain storage.  When farmers use the word water, they are
likely to think of lakes, rivers, wells, or containers of water.  They
think of water as a liquid which is very easy to see and to measure.
A farmer may not be familiar with the word moisture.  Moisture is a good
word because it can describe something which is wet or contains water
without looking wet.  For example, the earth can have moisture and not
look wet.   A plant does not look wet, but when you crush it, you will
feel moisture (wetness) on your hand.
Each kernel of grain has moisture inside.  But the grain kernel does
not look wet when you look at it.  The farmer can tell if it is wet by
cracking it between his teeth.  Wet grain is not hard because the water
inside is wetting the seed and keeping it soft, just like pouring water
on hard earth makes the dirt soft.  When the moisture leaves the grain
during drying, the grain becomes harder.  The dryer the grain, the harder
it becomes.

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Grains hold different amounts of water at different times:  the amount of
moisture in harvested grain depends mostly on the time of the harvest.
For example, grain harvested in the rainy season may have more moisture
than grain harvested in dry, sunny weather.
It is important to note that some grains must contain more moisture than
others when harvested, if they are to be harvested safely.  This is true,
for instance, of new varieties of rice.  This rice must be harvested
before it gets too dry, or much of the rice will shatter or fall off the
stalks.   Both maize and rice can be harvested when the moisture content
in the kernels is in the 20% range.  However, maize can be left in the
field to dry further before harvesting.  Rice must be harvested right
away and not be allowed to dry in the field.
Air contains moisture also.  Of course, the farmer cannot see this kind
of wetness when he looks at the air, because the moisture in the air is
in the form of vapor.

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Just as grains hold different amounts of water, air holds different
amounts of water.  Warm air can hold more moisture than cool air.
On a very hot day, there can be a lot of moisture in the air, When
evening comes and the temperature goes down, the air, now cooler,
cannot hold all the moisture it held when it was warmer.  So the
extra moisture falls out of the air and lands on the earth.  This
moisture from the air is the dew seen in the cool early morning.
As the sun gets higher during the day, the air temperature goes up.
The air, now warmer, can hold more moisture.  So the dew on the land
is taken up by the air.

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Relative Humidity
Many farmers will not be familiar with words such as relative humidity.
Nor do they really have to be.  It is not important to most farmers to
understand that relative humidity is a percentage measurement of the
amount of moisture actually in the air as compared to the maximum amount
of moisture that air at that temperature could hold.  Nor do most farmers
need to understand that if the moisture content in the air remains the
same and the air temperature goes up, the relative humidity goes down.
Relative humidity is a meaningful phrase only to those who can measure
it and apply the knowledge to drying times, etc.
Most farmers do not have instruments which measure relative humidity.
But they have good information if they understand two facts about air and
     1.  Warm air can hold more moisture than cold air.
     2.  Air at any temperature does not always hold as much
         moisture as it possibly can.  The amount it actually
         holds changes.   When air holds as much water as it
         possibly can (100% relative humidity), rain is likely.
Scientists say that grain is hygroscopic because it loses or gains (adds)
moisture from the air around it.  At this point, it would be easy to get
involved in a long discussion of moisture and vapor pressure.  For example:
     Since all things containing moisture have pressure, grain
     and air have pressure.  Grain dries in the sun because
     moisture vapor is moving from higher pressure in the
     wet grain to lower pressure in the air, until the grain
     and the air reach equilibrium vapor pressure.
     This can be explained somewhat more simply by saying that
     two things containing water will push that water back and
     forth until a balance is reached.   The more moisture there
     is, the harder the moisture can push.  That is, if there is
     comparatively more moisture in the grain than there is in
     the air around the grain, the moisture in the grain will
     push out into the air.
     The key to the drying process, then, is placing grain in the
     sun or in a drying machine so that the kernels of grain can
     be touched by warm moving air which has less moisture in it
     than the grain has.   The heat in the moving air will make the
     moisture in the grain evaporate.   The moisture will become
     water vapor and be absorbed and carried away by the moving air.
It is useful for a farmer to know that drying continues only as long as
the air around the grain is able to absorb more moisture from the grain.
If the air contains a lot of moisture, the grain is likely to take in that
moisture from the air.  The farmer should understand this fact because
it explains the need to keep dry grain away from moisture and/or air as
much as possible.  Grain that is not sealed in a closed container will
continue to exchange moisture with the air.  During the rainy season,
for example, grain will take on moisture if left in an open container.
In the hot, dry season, grain will lose the moisture again.

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Grain put into storage should not have more than a certain amount of
moisture inside its kernels.  Although the amount of moisture grain
can hold in storage safely can change, depending upon storage conditions,
some general moisture-safety percentages have been established.
The chart which follows(*) shows that maize can be stored safely at 13.5%
moisture (that is, 13.5% of the total weight of the kernel can be
moisture), in air which is 25-30 [degrees] C and has 70% relative humidity (that
is, the air at this temperature can hold 30% more water than it is
holding).   At this point the kernel of maize and the air are not going
to exchange moisture back and forth.  This is an equilibrium point.
This equilibrium is the condition good grain storage tries to set up,
but it is very hard to keep grain stored at conditions which keep
                                     MAXIMUM MOISTURE CONTENT FOR ONE
                                     YEAR (OR LESS) STORAGE AT 70%
      GRAIN TYPE          RELATIVE HUMIDITY AND 27 [degrees] C
        Wheat                                   13.5%
        Maize                                   13.5%
        Paddy Rice                              15.0%
        Milled Rice                             13.0%
        Sorghum                                 13.5%
        Millet                                  16.0%
        Beans                                   15.0%
        Cow Peas                                15.0%
Remember, the figures above are maximum recommended moisture levels.
Generally, farmers should dry their grain as thoroughly as possible.
    *  From "Handling and Storage of Food Grains in Tropical and Subtropical
       Areas," by D.W. Hall, published by Food and Agriculture Organization of
       the United Nations, 1970.
Grain which is dry and cool will keep for a long time if it is stored
correctly.   However, there are a number of bad things which can happen
to grain while it is in storage.  And moisture is a key part of most of
the process of deterioration (spoiling) that can occur in stored grain.
To discuss the role of moisture in the storage container, it is necessary
to talk about:
    *  grain condition
    *  temperature
    *  insects, molds, and grain heating.
Grain Condition
The farmer must store only clean, healthy grain which has been dried
to safe storage levels.
Broken grains and pieces of straw or dirt increase the chances of storage
trouble.   And, if the storage container does not keep out moisture
or insects, even healthy, clean, dry grain can deteriorate.  Trouble
is less likely to happen if the grain starts in good condition.
There are two kinds of temperature:  temperature in the air outside the
storage container and temperature of the grain inside the storage container.
Some things to remember about temperature:
     *  Low temperature is better than high temperature for
        grain storage.   Insects and molds do not grow at low
     *  Grain breathes very slowly at low temperatures.
     *  At low temperatures, little heat builds up inside the
        grain from the living and breathing of insects and
        molds -- and the grain.
     *  Rising temperatures outside the containers can increase
        the temperature inside the container -- particularly if
        the container is not shaded or is made of metal.
     *  Rising temperatures can lead to
        insect and mold growth.   Even in
        grain that looks clean, insects are
        almost always there to some degree;
        mold spores are present everywhere.
        As the temperature of the grain goes
        up, these insects and molds will
        start to grow.
     *  As the temperature goes up, molds and
        insects grow faster.   The grain respires
        more quickly.   If the grain contains
        a lot of moisture, this process goes
        even faster.
     *  Hot spots can form in areas of the grain where the most
        mold and insect activity is occurring.  These hot spots
        spread and cause great damage and loss of the stored

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The above points show how temperature and moisture work together.
Therefore, grain placed into storage should be as dry and cool as
possible.   Even then there can be a moisture problem during storage.
This problem often is the result of a difference in temperature between
the inside and outside of the storage container.  When cool air and
warm air mix in the stored grain, the warm air cools and may be forced
to lose moisture.  This lost moisture becomes water which can be seen
at the top and bottom of the storage container.  The following drawings
show what may happen when there are differences in temperature between
the inside and outside of the storage container:

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These changes caused by temperature can be seasonal, or they may be daily.
This depends upon where the farmer lives.  Obviously, it is best to keep
stored grain at a relatively constant temperature.  The storage section
will show various ways of dealing with this problem.
Insects, Molds, and Grain Heating
Remember the dew and how it forms because cold air and warm air cannot
hold the same amount of moisture?  This same thing is what happens in
stored grain when cold air and warm air meet each other because of
changing temperatures.   The farmer who understands dew will be able to
understand how his grain got caked and moldy even if it was dry when he
put it inside the storage tin or container.
The pools of water formed by the moisture forced out of the air make
the stored grain wet.  This wet grain begins to respire at a faster and
faster rate.   If there are insect larvae and mold spores present, they
begin to grow and reproduce.  Soon the insects, molds, and grain all are
giving off heat.  This process produces the hot spots spoken of earlier.
When the temperature gets too high, insects will leave the heated spot
and go out into the grain mass to find better living conditions.  Other
trouble spots then can develop.

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Now the background for the subject of grain storage is complete.  If
you have been using this manual with a farmer or group of farmers, they
now know what grain is in a scientific way; the relationship among grain,
water, air, and temperature; and some of the ways grain storage problems
occur.   In other words, they have some scientific ideas about good
grain storage.   The next section deals with the subject of preparing
grain for storage.  That discussion applies some of the ideas from this

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This section discusses the steps a farmer should take to prepare grain
for storage.   It gives these steps in the order he takes them.  Each of
these steps is looked at here as an important part of the storage
process.   Good harvesting, threshing, cleaning, and drying practices are
important for the success of any storage method a farmer may use.
Some grains, such as new varieties of rice, should
be harvested when they contain quite a bit of
moisture.   Other types of grain, such as maize,
can be much drier when harvested.  But even when
the grain can be allowed to dry in the field,
there is often too much moisture in the air,
or even rain, and the grain does not lose a lot
of its moisture.  Therefore, for one reason or
another, the farmer has to harvest very moist
grain.   Then he must somehow dry the grain to
about 12-13% moisture content.

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If the grain is a variety which can be allowed to
dry in the field, and if the weather is good, the
farmer can let his grain get as dry as possible
while it is still in the field.  In some dry, sunny
places, it is possible to shock and windrow the
grain after cutting it.  Wheat, for example, is
tied in small bundles that are stacked together
side by side.   Maize is also often stacked in
shocks.   This practice allows the grain to dry
further.   But this practice requires good weather.
And rodents, birds, and insects can attack the grain
while it is drying.

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Threshing is the separating of grain kernels from stalks and husks.   A
small-scale farmer usually cuts and threshes grain by hand.  When this
method is used, farmers must be careful to make sure all weeds and
straw are separated from the harvested grain.

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There are serious problems in most hand-threshing methods, especially
for small grains.  A common method uses trampling or beating of the grain
to free the kernels.  This method often causes cracking of the grain.
In addition, unless threshing is carefully done, much of the grain is
thrown away with the husks.

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No matter what method the farmer uses for harvesting and threshing, he
should aim for clean, whole grain.  There are machines available which
can harvest and thresh grain at the same time.  Most small farmers
cannot afford these machines.  And for the small farmer, hand harvesting
has advantages:   it is easier to separate weeds from the grain,
and less grain is lost during the harvest.
Clean grain keeps in storage much better than dirty grain.  After harvest,
grain often contains small amounts of straw, weed seeds, and dirt.  These
unwanted materials decrease the value of the crop if they remain in the
grain.   They also cause the grain to deteriorate during storage.  Dirt
holds moisture, insects, and molds.  Dirt also keeps air from moving well
through the grain.  Dirty grain heats more and deteriorates more quickly
than clean grain does.
Insects also must be removed from the grain.  Those which eat the grain
cause damage in several ways.  They destroy much of the grain by eating
it.   As they grow and multiply, insects produce heat which can cause
grain to spoil more rapidly.  Grain with a lot of insects in it brings
a much lower price than clean grain does.
Most modern harvesting machines get grain pretty clean.  They usually
blow air through the grain:  this removes very light materials such as
chaff, husks, and dust.  The grain then is sieved.   The pieces smaller
than the grain kernels are removed by passing them over a fine mesh
screen.   The larger pieces of waste are passed over a screen that has a
mesh size larger than the kernels.
This screening technique can be used even when a machine is not available.
However, it requires screens of proper mesh size.  When screens are not
available, or when a substitute cannot be found for them, there are other,
less effective cleaning methods.
One of the simplest methods of
grain cleaning uses the wind:
this method is called winnowing.
The grain is thrown upward in the
wind.   As it falls, the lighter
pieces -- dust, powder, broken
grain -- are blown aside by the
wind.   But the heavier stones and
pieces of earth fall with the grain.
For good cleaning, winnowing must be
done over and over.  Some grain is
always lost, and so the method wastes
grain.   Some farmers place this
waste material where chickens can
take the lost grain from it.

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Farmers also should clean their grain each time they move it to a new
storage place.   If this cleaning is not done, dirty grain from one place
may be mixed with clean grain from another.  Even grain that has been
cleaned quite well before may need cleaning again.  Insects do not need
a long time to get into grain.  Both the insects and their dirt should be
removed before the grain is added to grain already in the storage areas.
The farmer should remember that cleaning is important because:
    *  dirty grain deteriorates more rapidly in storage.
    *  clean grain does not heat as quickly.
    *  insects breed faster in dirty grain.
If moist grain is stored without air moving through it, the grain becomes
hot.   The grain respires more quickly and gives off more heat and moisture.
The grain can be damaged if the heat is too great.
    *  Heat builds up more quickly in wet grain.
    *  Molds form rapidly.
    *  Insects multiply faster.
    *  Grain can germinate (sprout) while still in storage.
It has long been known that meat, fish, and fruit can be preserved by
drying.   Dried fish and fruit are widely used for food.   These materials
do not deteriorate much even when stored for long times.  This is because
life processes usually occur very slowly when there is little moisture.
This is true for grain.  Well-dried grain deteriorates only slowly even
at fairly high temperatures.
In the Field
In order to dry grain, moisture in and on its kernels must be carried
away.   As the grain stands in the field, the dry air moving past it takes
up moisture from the grain.  This air, now moist, is then blown away
from the grain by the winds.

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The drying process is most rapid if the air does not contain much moisture
and if there is a wind.  Little drying of the grain occurs if the air
contains a lot of moisture, or if there is not much wind.

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Hot air passing through the
grain usually dries the grain
more quickly than cold air
does.   From the previous
section, it is easy to see
that there are three major
reasons for this:
    1.  Hot air can hold more water than an equal amount of cold
        air can.   When dry air blows through the grain, the hotter
        the air, the more water it can carry away from the grain.
    2.  Water evaporates more quickly when it is warm.   Hot air
        blowing past grain warms the moisture on the surface of
        the grain.   This moisture leaves the grain more quickly.
    3.  Hot air heats the grain itself.  Moisture deep inside
        the kernel moves through the kernel faster at high
        temperatures.   It moves to the surface of the kernel
        more quickly.   When this moisture reaches the surface,
        it leaves the grain and is taken up as vapor by the
After Harvest
The above facts also apply to drying grain after it is harvested.  Air
must pass through the grain to dry it.  Moisture between the kernels
and on their surfaces is carried away first.  The moisture deep within
the kernels must first come to the outside of the kernel.  Only then
can it be removed by the flow of air.  Air must be moving for drying
to continue.   Only if new, dry air enters the grain can the moist air
between the kernels be replaced by air which can take up more water
from them.   This is the principle behind some drying methods which
force cool dry air or warm dry air through the grain to speed drying.

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Grain drying methods and models are presented in the next section.
It is nearly impossible to dry any grain completely.  The last ten
percent or so of moisture in the kernel is tightly held by the kernel.
It can be removed only with great difficulty.  Luckily, grain stores well
with this amount of water in it.  In some cases, removal of this last
water harms the grain.
Whatever method a farmer uses to dry his grain, he must be careful not
to let the temperature in the drying grain get too high.  Too high a
temperature causes the kernels of some grains to burst.  Temperatures
which are too high (when drying maize and rice) cause breaking, cracking,
and discoloration of the kernels.  This leads to a decrease in milling
yield and protein quality.  Maize which is used for oil will produce
less oil.
Grain used for baking and milling can be dried at temperatures higher
than grain to be used for seed.  Grain used for seed should not be
heated above 40-45 [degrees] C.  High temperatures can kill the seed embryo, and
the seed will not germinate when planted.
The following are the highest safe temperatures for drying grain.
           USE                             MAXIMUM TEMPERATURE, [degrees] C
       Livestock Feed                                    75
       Food for Humans, except rice and beans           60
       Milling for Flour                                 60
       Brewery Uses                                      45
       Seed Grains                                       45
       Rice for Food                                     45
       Beans for Food                                    35
Note Well:   The drying temperature depends upon the use of the grain.
Drying at lower, rather than highest, temperatures usually gives a better
quality dry grain.  Also, as a rough rule, lower temperatures should be
used for very moist grain than for dryer grain.  It is better to take a
longer time, and use a lower heat, to dry moist grain than it is to run the
risk of parching or burning the grain.
Grain that is too moist will heat in storage.  All stored grain should
be examined frequently to see if it is heating.  Heat build-up deep
within the grain is a serious danger signal.  Unfortunately, waiting
until you can feel the heat in the grain is waiting too long.
Various electrical moisture testing devices are sold.  They are seldom
available when and where they are needed.  Most of them are complicated
and expensive.   An appendix to this manual contains a discussion
of moisture meters.  This will show you the kinds of commercial
meters which are available.
             Extension workers should know that
             grain moisture percentages are calculated
             in the following way:
   PERCENT MOISTURE =        weight of completely dry grain
                      100 x                        
                            total weight of wet grain
             There are several ways to mechanically
             measure the amount of
             moisture in grain in order to
             make this mathematical calculation.
             Unfortunately none of these methods
             are very simple or inexpensive.
Fortunately, an experienced farmer can usually
tell if grain is dry enough for storage.  The
method used by the farmer varies from region
to region and depends upon the type of grain.
However, two methods used by experienced
farmers in many places are:  (1) pressing the
kernel of grain with the thumb nail to see how
hard it is (dry grain is hard to press), and (2) crushing the grain
kernel between the teeth to make sure it is hard enough (dry enough)
for storage.   Some people talk of testing to see if grain is dry enough
by smelling it for an "off" smell or by rattling grain kernels in a tin
can to hear if the dull sound of wet grain has given way to a sharper
sound of dry grain.

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The scope of this first manual edition can not be broad enough to allow
us to add specific drying instructions and suggestions for each type
of grain.   Future editions may be able to do this.   If your area is
more involved with wheat, and you feel there are additional facts farmers
should know, or there are drying methods you have found particularly
helpful and would like to share with others around the world, send
them in!
If there are plans for threshers and winnowers which could be made and
used effectively by others, these also could be included in future
editions of this manual.
                      PREPARING GRAIN FOR STORAGE
Suggested Use:   A shortened version of the text.   This could easily
                be illustrated and translated for use by farmers.
     *  Check the grain in the field before you harvest.   Make
        sure the grain is free of insects and disease.
     *  Clean old dirt and grain from harvesting tools.
     *  Remove old grain and dirt from carts or anything
        used to carry the grain from the field to the
        storage place.
     *  Use insecticide on all bins, sacks, and equipment.
        Remember to ask your extension worker for directions.
        Always use insecticide carefully.
     *  Harvest the grain carefully.  Do not break the grains.
        Broken grain will not store well.
     *  Keep the grain cool and dry between the time you
        harvest and the time you store it.
     *  Clean the grain carefully.  Insects and molds like
        to live in harvested grain.
     *  Sift, screen, winnow, or pick out by hand all dirt,
        straw, chaff, broken pieces of grain, rocks, and
     *  These materials hold water.  The grain dries better
        and faster after all the dirt is removed.
     *  Good drying is very important.  Insects and molds
        like moist grain.  Dry grain is harder for them to
     *  Some farmers dry grain in the field.  Insects, rodents,
        and birds can attack this grain easily.  Also, this
        grain can get wet if it rains.   Maize can be dried
        better in the field if the stalk is broken, and the
        ear hangs upside down.
     *  It is better to take the grain out of the field.
        You can bring the grain to a special drying place
        and dry it in the sun.
     *  Keep the grain off the ground while it is drying.
        Grain picks up moisture from the ground.
     *  Spread the grain on mats or flat boards to dry in
        the sun.
     *  Some farmers spread the grain on large trays.   The
        trays are put out when the sun is shining.  The
        trays are placed under a roof when it rains.
     *  Insects will leave grain that is in the sun.   Insects
        do not like hot sunlight.
     *  You must watch the drying grain to protect it from
        rodents and birds.
     *  Some farmers like to use open storage places called
        cribs.   These cribs have roofs on them, and they are
        built on legs.
     *  These cribs work well for unshelled maize (maize that
        has not been removed from the cob, or inner part of
        the ear) or for unthreshed millet, sorghum, or rice.  
        Maize can dry in the crib until it is dry enough for
     *  Some farmers build large drying machines to dry their
     *  The grain is put in the dryer.  A fire is lit under
        the grain to warm and dry the grain.
     *  Artificial or mechanical dryers can be used by groups
        of farmers to dry their grain.   Your extension worker
        can tell you about these dryers.
     *  Test the grain when you think it is dry.   The grain
        must be very dry before you put it in storage.
     *  Dry grain is hard.  It is hard to break it with your
     *  Extension workers sometimes use special tools to see
        if the grain is dry.   These tools are called moisture
     *  When the grain is dry, look for insects again.   Turn
        the grain over with your hand.   You can see insects
        crawling around.
     *  Sift out the insects.  Or spread the grain in the sun.
     *  Destroy the insects you take out of grain.   Burn them.
        They will go right back into the grain if you do not
        burn them.
     *  Put the grain into storage containers before insects
        can get into it again.
     *  Put each kind of grain into a separate container.
     *  Do not put new grain with old grain.  Store new grain
     *  Use old grain first.
     *  Store rice with the outer coat on.  This coat helps
        protect the grain from insects and mold.  The grain
        will be good for a longer time.
            5 GRAIN DRYER MODELS
This manual already has talked about the need for drying of the grain.
Unshelled maize, rice, millet, or sorghum often is stored in cribs for
further drying.   The ears, or heads, do not pack tightly.  Because the
cribs are open to the wind, air moves through the stored grain and dries
it.   Even so, storage in cribs is more effective in the dry season.  The
more humid air of the wet season may actually add moisture to the grain.
In addition, insects and rodents can cause serious damage to unprotected
grain stored in cribs for long periods.
Threshed grains, particularly those with small kernels like millet, dry
very slowly during storage.  The kernels pack tightly together.  As a result,
air cannot move easily through the grain.  Such grains can be spread
in thin layers in the sun for drying.  If possible, the grain should be on
a screen to let air enter the bottom.  The grain should be tumbled (stirred)
often and carefully.  The grain kernels can crack if they are stirred too
The newer drying methods described
here use heated air to dry the grain.
Hot, dry air is blown through the
grain.   These methods dry the grain
quickly and well.  Most of them require
the burning of fuel to heat the
air.   This fact, together with
the cost of building the machine,
often limits the usefulness of
drying machines for use by
small farmers.

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Improved Traditional Methods
A farmer has to think about a lot of things before he can decide which type
of drying method to use for his crop.  Here are some of the considerations
he must keep in mind:
     *  Does his present method work?  If it does, why change it?  If
        it does not work, why not?
     *  How much money will he have to spend for a new drying method?
     *  Would he be able to maintain a new drying machine?   Could he
        fix it?   Does he have enough time to operate it?
     *  Would the cost of the dryer be easy for him to get back because
        of better storage leading to more grain to sell?
     *  Would it be better to join a group of farmers and pay for the
        cost of a dryer with a group?   Or does the farmer dry enough
        grain to make use of a dryer by himself?
You will probably be able to help by offering alternatives.  For many farmers,
an improved method of crib drying for maize or sun drying for smaller,
threshed grains, would be a step easily taken.  Such a step would insure
a much better crop.

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Here are some ideas for sun-drying grain:
     *  Spread the grain in thin layers on trays which can be carried.
        Stack the trays under sheds or roofs at night to protect the
        grain from dew or from rain.
     *  Make trays with fine-mesh screening for the bottom.   Support
        the trays so they do not rest on the ground.  The screening
        lets dust and straw fall out of the grain.  Put the trays on
        top of each other under roofs or sheds at night and when it
        is raining.
     *  Find a plastic sheet.  Or use several plastic sheets joined
        together.   You need a sheet about 10m x 3m.  The plastic should
        be at least .004 gauge thick.
     *  Build a mound of hard-packed earth to place the plastic on.
        If you use level ground, build a dike of earth around the area
        on which the plastic will be placed to protect the drying
        grain from water.
     *  Make sure there are no rocks, wood and sharp things on the
        ground where the plastic will go.   The plastic tears easily.
     *  Place the plastic in the prepared place.
     *  Attach the narrow end of the plastic to straight poles made from
        bamboo or other smooth material.
     *  Put clean grain on the plastic.  Do not make the grain more than
        5cm deep.
     *  Stir often so the grain will dry faster.   Turning and stirring
        makes sure all parts of the grain are touched by air and sun.
     *  The rake or other tool used to stir the grain must have smooth,
        rounded edges.   This tool then will not damage the plastic or
        the grain.
     *  As the grain dries, moisture from the grain collects on the
        plastic.   After the grain has been drying for two hours, push all
        the grain to one half of the plastic.
     *  Let this plastic dry for 5 minutes or so.
     *  Push all the grain to the other half of the plastic that is now dry
        and let this half dry for 5 minutes.
     *  The plastic sheet should be aired in this way every two hours while
        drying is going on.
     *  Cover the grain at night.  Push all the grain to one end and fold
        the plastic over as a cover.
     *  Or place an extra piece of plastic over the grain.
     *  Remember to put soil, boards, rocks, and heavy things on the corners
        and edges of the plastic cover to keep it from blowing off.

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Maize holds a great deal of moisture inside its kernels and husk.  When
maize is harvested, the moisture content is high.  It must be much drier
before it can be put into closed storage containers.  If maize is put into
a closed container right after harvest, molds cause heavy losses of grain.
Drying Maize
Harvested maize must have air passing around it to dry the kernels.  When
the kernels are dryer, they can be shelled (taken off the cob) and stored
in airtight containers.  To dry maize before shelling, some farmers keep
the husks on the ears.  Then they tie the husks into bunches and hang these
bunches in trees.  Some farmers hang these bunches on poles set into the
ground or put them in the roofs of cooking or living shelters.
Sometimes farmers remove the husks and pile the ears loosely in open-weave
basket granaries or in covered crib granaries.  These containers partly
protect the grain from rain.  Storing maize this way allows air to pass
over the grain and dry it better.  This way of storing the maize while it
is drying helps protect the maize from mold.
But insects remain a big problem.  They can attack maize drying in cribs
easily.  Many farmers choose to leave the husk on the maize.  This does
provide some protection from insect attack -- particularly in traditional
varieties of maize where the husk is tight and fits closely over the ear.
In newer, hybrid varieties of maize, the husk is smaller and the ear is
larger.   These varieties are more easily attacked by insects.  Maize with
the husks left on will take longer to dry because the air cannot pass
freely over the ear.  Also, the husks are full of moisture -- increasing
drying time and the risk of molding.
So, a good way to dry and store maize would:
      1)  allow the maize to dry without the husks.
      2)  control insect attack at the same time.
Crib storage, already done in many countries, seemed a good method needing
only slight improvement.  Therefore, much work and study were done to
design improvements into crib storage to allow for both faster drying and
effective use of insecticides.  Much of the improvement in the crib storage
method is based on proper use of insecticides.
Insect Control in Cribs
To reduce losses due to insects, a number of insecticides have been
tested for open crib storage.  The maize put into the crib must have the
husks removed so that the insecticide can cover the whole surface of the
Apply the insecticide to the maize ears in layers.  Put down a layer of
ears 20-25cm deep.  Dust the layer with insecticide.  Put down another
layer of ears, and then more insecticide.  Continue until the crib is full
When the crib is full, put insecticide on the outside walls of the crib
to prevent insects from entering.
The wind, rain, and sun all can affect how long the insecticide lasts.
You can put more insecticide on the outside of the crib every three to
four weeks.   Look at the maize in the crib every few weeks to see if the
insecticide is still working.  The insecticide put inside the crib will
last only four or five months.  But while it is working it can reduce the
amount of maize damaged by insect attack.
After four months, check the grain moisture level.  The maize may be dry
enough to shell and store in sacks or bins.  The maize is dry when the
kernels crack sharply between your teeth and are not soft.  If the grain
is not dry enough, remove all the maize and put it back into the crib
again, layer by layer, dusting with insecticide as you go.
Faster Drying
Keep the crib no wider than 1m.  Between 60 and 100cm are good widths for
dryer/storage cribs.  The narrow width helps maize to dry more quickly.
Air cannot move through wider cribs to cool the grain in the middle.   The
grain in a wider crib will heat, and be attacked by mold and insects.
Rain which wets the grain through open crib walls is not generally a problem.
Only the surface of the maize on the sides gets wet, and this dries
quickly after the rain stops.  This rain causes no increase in moisture
content of the grain if there is sunny weather afterwards.
The following plan is a modification of a crib designed and tested by
the Nigerian Stored Products Research Institute and the FAO Rural
Storage Center at IITA, Ibadan, Nigeria.  The plan is for a 2m long
crib.   It stores 800kg of maize ears (this will give 540 kg of shelled
maize).   A crib which is 1,50m high, 0 60m wide and 1m long will store
400kg of maize ears (yields 270kg of shelled maize).
Some General Remarks About The Improved Maize Drying and Storage Crib
       *  Use materials that are easy to find in your local area.
       *  The crib will work best if it is no wider than 60-70cm.
       *  A good height for the crib is 2,00-2,25m from the ground to
          the roof.   There is at least 50-75cm between the bottom of the
          crib and the ground.   Most rats cannot jump this high.
       *  If bamboo in your area is attacked by insect borers, use
          another local wood for the legs.  Make sure the wood is termite
          proof.   These legs must have rat guards put on them.
       *  The long sides of the crib must face the sun.   That is, they
          should face the east and west.   The short sides will then face
          north and south.
       *  Make the crib larger by adding more sections.   Make it longer.
          Do not make it wider.
Tools and Materials
This is a guide.  You can use what you have available.  The frame is
bamboo.   If bamboo is not available in your area, or if the bamboo in
your area is attacked by insect pests, use wood that is resistant to
termites or any other pests.  Lash it together the same way you would
lash bamboo.
For the building frame (all bamboo or substitute):
     (a)  3 vertical supports, 3.5m long, with V-notches and lashing
          slots in one end of each one
     (b)  3 vertical supports, 3m long, with V-notches and lashing slots
          in one end of each one
     (c)  2 horizontal roof supports, 2.5m long
     (d)  2 horizontal platform (floor) supports, 2
     (e)  6 vertical platform supports (with V-notches in one end of each),
          1.5m long
     (f)  6 notched horizontal width spacers, 70cm long
     (g)  25 poles, 95cm long, for the platform surface
For the wall bracing and covering (raffia, small bamboo or other wood):
     (h)  8 cross braces (optional if frame is very strong):
          * 4 must be about 2.5m long
          * 4 must be about 1.70M long
     (i)  8 wall supports, 2.25m long
     (j)  8 wall supports, 1m long
     (k)  raffia or other strong slats for the wall covering.   Tie these
          together into a mat.   The finished mat should be about 6m long
          and 1

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For the roof (all bamboo or substitute, except for purlins, and roof
covering and loading cover):
     (l)  2 horizontal pieces, 3.25M long
     (m)  3 cross pieces, 1m long
     (n)  2 angle braces, 1m long
     (o)  7 purlins, 3.25m long.  Six of these will be lashed across
          the cross pieces to support the roof covering; one may be
          attached to the front loading cover.
     (p)  raffia mat or grass for thatch to cover the roof, and also for
          the front loading cover.   You will need a horizontal piece at
          least 2.25m long to weave the loading cover material onto -- it
          need not be bamboo or of a large diameter.
For rat guards (if you need them):
          See Section 6, Part 2 of this manual for directions on making
          rat guards (baffles).
For the lashing material:
     (q)  You will need plenty of rattan, rope or tie vine for lashing
          all the wood pieces together.

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1.   Select a site.
     *  Find a good site for your storage crib.  Keep the crib away
        from the fields.   This stops insects from flying to the drying
        grain from the fields.
2.   Prepare your materials.
     *  Collect all the materials you will need.
     *  Make V-shaped notches in one end of each
        of the three 3.5m vertical supports (a),
        and cut some grooves on each side just
        beneath the notches to provide a hold for
        the lashing there.   Do the same on one end
        of each of the three 3m vertical supports

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     *  Make V-shaped notches in one end of
        each of the six 1.5m vertical
        support posts (e).

51ap49c.gif (285x285)

     *  Make holes all the way through
        each end of all six 70cm
        horizontal spacers (f).

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     *  Organize all the pieces, or mark them with the appropriate
        letters, so you can find them quickly during construction.
3.   Make holes in the ground for the legs.
     *  Mark spots for holes for the vertical supports (legs)(a) and
        (b) on the ground.   Make a mark for the first hole; measure
        1m and make another mark.   Measure 1m from that mark in the
        same direction and make a third mark.  You should now have
        3 marks in a straight line.   Each mark will be the center of
        a hole.
     *  Make three more marks, each 1m apart, in a line parallel to
        the first line and 75cm away.   Each of the three new marks
        should be directly opposite one of the first marks and 75cm
     *  Dig six holes, each centered on one of the marks.   Make the
        holes 50cm deep and wide enough so that two vertical supports
        will fit down into each one.

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4.   Erect the vertical supports.
*   Lay the three 3.5m vertical
   supports (a) on the ground
   1m apart, with their ends
   lined up.  Lash one of the
   2.5m horizontal roof supports
   (c) to the notched ends.
*   Lay the three 3m vertical
   supports (b) on the ground
   in the same way and lash
   the other horizontal roof
   support (c) to the notched
*   Place the two assemblies
   into the holes.

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5.   Erect the vertical platform supports.
*   Place the vertical platform
   supports (e) into the holes
   on the insides of the vertical
   supports you have
   placed in the holes.   Make
   sure the V-notches are
   facing upwards.
*   Tie the platform supports to
   the longer supports temporarily
   until the next step is

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6.   Install the platform support framework and make the structure
*   Place the two horizontal
   platform supports (d) in the
   V-notches of the platform
*   Lash three of the notched
   horizontal spacers (f) to the
   vertical supports (a) and (b),
   across the width of the crib.
*   Level and square the framework.
*   Fill the holes around the
   vertical supports with small
   stones and soil.   Tamp down
*   Lash all joints tightly.

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7.   Finish the platform.
*   Lash the twenty-five
   95cm poles (g) next
   to each other on the
   horizontal platform
   supports.  This forms
   the platform.

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8.   Install the cross braces.
*   If you think the frame is not
   sturdy enough by itself, lash
   the cross braces (h) loosely
   to the vertical supports on
   the outside of the crib.
*   The 2 1/2m cross braces are
   paired on the long sides of
   the crib, and the 1,70m cross
   braces are paired on the
   ends of the crib.
*   Each brace should extend from
   somewhere near a top corner
   to somewhere near the opposite
   bottom corner.   Leave
   room for a loading cover on
   the higher side of the crib.
*   Make sure the frame is straight
   and even.  Lash the braces

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9.   Install the wall supports and wall covering.
*   Lash four of the 2.25m wall
   supports (i) to the vertical
   supports along the inside of
   one of the long sides of the
   crib.  Lash the remaining four
   supports to the inside of the
   other long side of the crib.
*   Lash four of the 1m wall supports
   (j) to the vertical
   supports along the inside of
   one end of the crib, and four
   of them along the inside of
   the other end.
*   Lash the already-prepared wall
   covering, 6m x 1.5m (k), to
   all the wall supports on the
   inside of the frame.

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10.   Build the roof.
*   Call the high side of the crib
   the front and the lower side
   the back.
*   Measure the distance between the
   centerlines of the front and the
   back horizontal roof supports (c)
   which are lashed to the tops of
   the vertical supports (a) and (b).
*   Lay out the two 3.25m horizontal
   roof pieces (l) on the ground so
   their centerlines are the same
   distance apart as the measurement
   you have just made.
*   Lash the three 1m cross pieces
   (m) on top of the horizontal
   roof pieces, 1m apart.   When the
   roof is placed on top of the frame, the cross pieces should cross over
   the ends of the vertical supports of the frame.

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*   Lash the two 1m angle braces (n) to the horizontal roof members so
   that they extend diagonally across the two spaces in the roof frame.
*   Lash six 3.25m purlins (o) on top of the three cross braces so that
   they extend longways along the roof frame.  Lash the first and last
   purlins near the ends of the roof cross braces.
*   Lash raffia mat in overlapping layers to the roof frame.

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11.   Install the roof.
*   Place the roof on top of
   the frame as shown
   (looking at the end).
*   Lash the roof in place.

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12.   Make and install a
     front loafing cover.
*   Lash raffia mat to a 2.25m
   long bar to form the front
   loading cover.   The mat should
   be made large enough to hang
   down beyond the top edge of
   the wall covering when the bar
   is lashed in place up under
   the front edge of the roof.
*   Lash the bar holding the raffia mat up under the front horizontal
   roof piece.

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13.   The crib is ready for use.
   Load the crib.   Lash down the bottom corners of the loading cover
   to the frame during drying and storage.

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                 NEWER DRYING METHODS
Some farmers have more money and are more in
need of a faster, more reliable way of drying
their crops.   Controlled drying, or drying
with a device which creates heated air for
drying, can be very helpful to farmers who are
ready and able to make use of newer methods.
Used appropriately, these drying methods can
help a farmer to:
       *  harvest earlier and get his land
          ready for a new crop sooner.
       *  avoid grain losses to insects,
          birds, and rodents during long
          natural drying times.
       *  store better-prepared grain, keep it in storage longer, and
          take it out in better condition.
       *  make more money from the sale of his grain.

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Four different dryer plans are presented here.  Two are made using oil
barrels and are heated with a fire.  The Philippines Rice Dryer uses a
fan and also uses heated air.  The solar dryers are three variations of
the same idea.
Be Sure a Dryer Will Suit Farmers' Needs
There are several factors which may determine the usefulness of faster
drying to farmers in your area.  It is not possible to give guidelines
for what a farmer could do in every case, but these are some of the basic
The Storage Method.  It will not be as useful to build a dryer that dries
grain to a low moisture level, and then store the grain in something
which will not keep it this dry -- such as cribs, unsealed gourds or
baskets, sacks, most kinds of earthen pits, or mud-walled structures
which do not have extra protection against moisture.  Airtight storage
will make the use of these dryers worthwhile.
Type and Condition of Grain.  Rice will crack easily in high-temperature
drying.   Newer varieties of rice must be harvested when they still contain
around 25% moisture; since the husks (containing moisture themselves)
must be left on while drying, and the rice grains will be tightly packed,
a very long time in the dryer would be needed.  In the two oil barrel dryer
designs, heat is not likely to flow evenly through the tightly packed
kernels:   and much rice would
be damaged by cracking.  If
fans are added to the oil
barrel dryers to force a more
even flow of warm air up through
the grain, farmers should be able
to dry rice successfully.  The
Philippines Rice Dryer uses this
method.   It may be difficult or
impossible to dry rice in solar
dryers.   Other grains which also
pack tightly, but give up their
moisture more easily, and are not
so likely to crack and shatter,
may be safely dried as long as
not too thick a layer is put
into the dryer at one time.

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Moisture in Grain.  Drying very moist grain will take longer.  The safest
way to dry moist grain is for a longer time at a lower temperature.   It
would be difficult to avoid overheating portions of the drying grain
during a long period of time if the temperature were not kept down.
It is difficult to control the drying temperatures accurately in oil
barrel dryers without fans and in solar dryers.
Moisture in Air.  The weather in your area will
affect how long the grain takes to dry.  In a
wet, cold climate or season, grain will take
longer to dry than in a dry, warm place.
Heated-air dryers might be very useful
where drying must be done in wet or cold
conditions which cause farmers to lose
grain to insects and molds during
long natural drying times.  But,
at least in the cases of the
oil barrel and solar dryers,
this must be weighed against
problems caused by relatively
long drying times in the

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Fuel.   What kinds of fuel are available, and how much
does it cost?   You must know this to determine the
value of heated drying, especially if you expect longer
drying times in a dryer.  Firewood is not always
plentiful -- or even available -- in an area.  Even if
available, it may be costly.  Maize cobs or some other
natural fuel may be available.  Farmers may have to
pay the labor costs for gathering these fuels.  Try
to be sure farmers will not be spending more on fuel
than they will be saving by marketing more and better
quality grain.

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Other Important Factors.  If the grain is to be used to seed, it should
not be heated beyond 45 [degrees] C.  It will be difficult or impossible to control
the drying of seed grain in these dryers.
Other possible costs, the availability of some materials, and
cultural values or local preferences must also be taken into account.
Some Notes on the Dryers
There are many dryers being developed all over the world.  But much of
this research is being carried out for use in large-scale drying operations.
This manual is concerned with the small-scale farmer and his problems.
The drying method he chooses must be appropriate for his situation.
The two dryers made out of oil barrels and hand-rammed earth or mudblocks
have only one part which may be expensive -- the oil barrels themselves --,
but the materials are available almost everywhere.  In the Pit Oil Barrel
Dryer the barrels are sunk into a pit.  The Simple Oil Barrel Dryer is
built entirely above ground.  They each require mostly simple labor and
would be good projects for a group of farmers.

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The Philippines Rice Dryer is made from wood and spare auto parts.
A fan provides reliable air flow and more even heating.  Oil, kerosene
or rice hulls may be used for heating fuel, and a small gasoline or
diesel engine, or an electric motor may be used to power the fan.  It
requires more in the way of materials.  Thus it may not be usable by
many farmers because of unavailability or high cost of materials.  But
the plan is included because there are farmers who are interested in
this kind of machine, and it does represent a relatively small-scale,
appropriate method of drying.
The solar dryers provide
faster drying and require no
fuel.   By enclosing the drying
grain, they retain the heat
of the sun better than just
spreading the grain out in
the sun to dry.   They require
little or no maintenance.
Except possibly for plastic
sheet or corrugated roofing,
all the materials should be
available almost everywhere.
One of the models' heating
capacity can be augmented
by adding a fire and a flue
under the grain bed.

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Again it is important to say that these dryers and drying methods are
included here to provide good examples of drying choices farmers might
be interested in.  If a method is not quite right for the farmers in
your area, perhaps only a slight change will be necessary.  You may
discover you can use ideas from one plan in another plan.  Let us know
if VITA can help make one of these plans more useful.  If you know of
a plan for a small-scale dryer useful to farmers which is not included
here, send it to VITA for inclusion in the manual.
                     A SIMPLE OIL BARREL DRYER

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This design is based on material prepared in 1973 by the Institute for
Agricultural Research at the Ahmadu Bello University in Zaria, Nigeria.
It is similar to the Pit Oil Barrel Dryer, but it is easier to build.
It rests on the ground so you do not need to dig any pits or trenches.
The drying grain is placed on a screen floor above four oil barrels
fastened together.  Warm air from the fire -- which is built in the front
half of the barrel chamber -- passes through the barrels and out the
chimney.   This warms the air around the barrels, which rises through the
screen floor and dries the grain.
Grain can be harvested without waiting for any drying in the field and
during any weather (if you build a shelter over the dryer).  Problems of
insect and rodent damage during drying in fields or cribs are avoided.
Construction materials are easy to find in most places.
It is better for a group of farmers to share in the building and use of
this dryer.   Make sure there is enough fuel in your area to operate the
dryer.   Firewood or maize cobs will work well.   Placing a fan to force
air through the barrels will reduce the amount of fuel needed.
In this plan mudblocks are used to make the walls.  Hand-rammed earth may
also be used without putting it into blocks first.  You may substitute an
available local material that will be as strong and resistant to wear and
heat, such as burned brick.  Sandcrete (cement and sand) or concrete blocks
will crack with the heat.  If banco (earth and water) is already used for
construction in your area, the same high-clay-content soil will work well
for the dryer.   You may mix in cement with low-clay soil to build earthen
This dryer is made with four barrels.  You can build one with more or less
barrels.   If you make it too much longer you may have trouble getting a
good draft from the fire going through them.  You should also narrow the
width of the dryer somewhat if it is longer, so as not to overload its
heating capacity.  You can make a shorter dryer wider.  A smaller dryer
might also be very useful to dry smaller fruit or vegetable crops.
Tools and Materials
           *  4 220-litre oil barrels
           *  about 375 mudblocks, each measuring 15 x 20 x 25cm
           *  wood to make a form for the mudblocks
           *  about 2m of heavy wire, to join the barrels
           *  3 strips of small-mesh screen, each about 180cm long
              and a few centimeters wide, to cover joints between barrels
           *  a little cement and some sand to make mortar for sealing the
              joints between the barrels
           *  13 6-10cm wide logs for drying floor supports.   Cut them about
              2m long, equal to the outside width of the dryer.
           *  6.5 or 7 square meters wire mesh, for the drying floor
              about the same area of heavy woven mats, plus a total of 10m
              of wire mesh strips about 20cm wide
           *  OPTIONAL:   materials for making concrete, plus reinforcing rods;
              or heavy metal bars.   These will make reinforcing crosspieces
              across the barrels in the front and back walls of the dryer.
1.   Select and prepare a site.
        *  Select a site that is well drained and can easily be made level.
        *  Plan to place the dryer so the chimney will be on the downwind
           side of the prevailing wind during the season when the dryer
           will be used most.
        *  Build up the ground on the site a little so rainwater will not
           collect around the dryer.   Make it level.   Make the raised and
           level area about 6,50m x 4m.
        *  Tamp the earth down firmly so it will not shift or crumble
            under the finished dryer.
2.   Assemble the oil drums.

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        *  Cut both ends from three 220 litre barrels.

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        *  Cut one end from a
           fourth barrel.   Cut a
           hole about 20 x 20cm
           across near the edge in the
           other end of this barrel.   This
           will make an opening into the chimney.
        *  Punch four evenly spaced holes
           around the rim of each barrel
           where it will join another
        *  Join the four barrels together
           by tying pieces of heavy wire
           through the punched holes.
           Twist the ends and press them
           down flat against the barrel.

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        *  Save two of the cut-off barrel
           ends to use later as dampers,
           one at the front entrance to
           the barrels and part of the
           other over top of the chimney

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3.   Make mudblocks.
        *  Make a form out of
           wood to mold mudblocks
           with.   One
           that will make
           three at a time
           might be a good
           size.   Make it so
           that each finished
           block will measure
           15 x 20 x 25cm.
        *  You will need about
           375 mudblocks.   Let them dry
           hard before using.

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4.   Begin the dryer walls.
        *  Mark the outside dimensions of the dryer on the dirt foundation
           you have made.   It will be a rectangle measuring about 3,50 x 2m.
        *  Call 3,50m the length of the sides and 2m the width across the
           front and the back.   Make your marks so that the front of the
           dryer will sit back about 2m from the edge of the raised and
           levelled earth foundation.   This will leave about 1m at the back.
           Leave about 1m on each side.

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        *  Allow for variations in the actual size because of differences
           in the mudblocks and spaces between them for mortar.
        *  Make a mixture of mortar out of the same material you used for the
           blocks.   Add just enough water so it is not too watery.
        *  Lay down the first layer of mudblocks.  Place blocks so that 20cm
           is the thickness of the walls and 15cm is the vertical dimension.
        *  Mortar between the blocks.  Allow about lcm between blocks for a
           good mortar joint.
        *  It is important to make the right distance between the front and
           the back walls.   Since the assembled oil barrels will be about
           3,45m long, make the distance between the inside edges of the front
           and back walls about 3,10m.   This will allow the ends of the barrels
           to rest firmly on the first layer of blocks at each end.  Later
           they will be enclosed around the sides by the finished end walls,
           making a good seal against smoke from the fire leaking around the
           barrels and passing up through the drying grain.
        *  The three spaces along each side wall will be air vents.   When the
           dryer is in operation cool air will be drawn in through them,
           warmed, and then rise through the grain to dry it.
        *  Make the air vents each about 15cm across.   If you have trouble
           getting a 3,10m distance between the inside edges of the front
           and back walls, you may change the size of the vents a little.
5.   Place the barrels.
        *  Place six free-standing blocks down the middle of the dryer.
           These will support the barrels.  Getting the barrels up off the
           ground helps air to move around them and also reduces the chance
           of their rusting.
        *  Put a layer of mortar on each of the blocks down the middle of the
           dryer and on the center part of the front and back walls where the
           barrel ends will touch.

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        *  Lay the barrels in place on the mortar and brace them temporarily
           with sticks if they want to roll.  Make the chimney end of the
           barrel assembly flush with the outside edge of the back wall.
           This should cause the front end of the barrel assembly to lie most
           of the way across the front wall.  Make sure the hole that will
           let smoke into the chimney is on the top of the end.
        *  Seal the joints between the barrels.  Place a strip of screen
           around each one and plaster with a mixture of mortar, one part
           cement to eight parts sand, and water.
Test the seals at the joints.  Light a smoky fire in the first
or second barrel from the front and see if smoke escapes anywhere
except the hole for the chimney.  Don't let it burn long enough to
dry the mortar on the joints.  Keep the mortar damp until it is

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6.   Continue the walls.
    *  Lay down five more layers of mudblocks.
    *  Lay the blocks so that, as much as possible, each block crosses
       over a joint between blocks in the layer below.  This will make
       the walls stronger.
    *  The air vents are only as high as the very first layer of blocks
       (15cm).   Span over top of each vent with one full-size block.
    *  To make good continuous layers of blocks you will have to cut
       some blocks into smaller sizes.
    *  Bring the blocks in the front and back walls as close as you
       can to the sides of the barrels.   Fill in the spaces completely
       with mortar so there will be no air leaks.  For added strength
       you can mix some cement with this mortar.
    *  If you think the ends of the barrels are not strong enough to
       support three or four layers of blocks above them, then make
       crosspieces out of reinforced concrete or use iron bars to put
       across the top of the barrel ends.   Make them longer than the
       width of the barrels.   Mortar them into place in the wall, and
       make the tops even with the top surfaces of the walls.

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7.   Make a drying floor screen.
    *  Prepare screen to the right size for the drying floor.   Assemble
       whatever size sections you have by overlapping about 5-10cm and
       fastening together with thin wire.
    *  The overall size should be about 3,30 x 1,80m.   This will allow
       about 10cm on each side to be embedded into the walls.
    *  Check the size of the screen by stretching it lightly across
       the top of the dryer.   If it overhangs beyond the outside edge
       of any wall when it is centered, trim it back.  If it is too
       small, add some screen where it is needed.  When you are
       satisfied, set the screen aside.
    NOTE:  Small-mesh screen is best.  But chicken wire can be
           used.   Place straw mats over chicken wire, or other
           large-hole screen, so grain will not fall through
           the holes.
           Some kinds of woven mats are very strong.  These can
           be used in place of screen.   In some places, screen
           may be costly.   If you use mats in place of screen,
           it would be best to prepare some strips of metal
           screen to embed around the insides of the walls and
           fasten mats to.   Then, if the mats later rot or weaken
           around the edges (or anywhere), there will be
           something to fasten new mats to.
8.   Place the drying floor supports and screen; finish the walls.
    *  Put a layer of mortar
       down on the top of each
       side wall.

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    *  Lay the thirteen logs
       down on the mortar,
       from one side wall to
       the other.   Space them
       evenly.   You should
       leave about 15cm between
       each one and between
       the log on each end and
       the end wall next to it.
       The 15cm may be a little
       different; it will depend
       on the size of the logs.
       The log ends should come to
       the outside edge of each side

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    *  Fill the spaces between the logs with mortar up to the tops
       of the logs.
    *  Build up the front and back walls and the corners of the
       dryer to the same height as the tops of the logs.
    *  While the mortar is still wet on the tops of the four walls,
       lay the screen you have made in place on top of the logs.
       Center it so about the same width extends over each wall.
       Stretch any wrinkles or kinks out of it.
    *  Place a thick layer of mortar over the screen the width of
       the wall so that it fills the holes in the screen and gives
       a good base to lay mudblocks on.   Lay mudblocks in the usual
    *  Lay down two layers of mudblocks above the screen.   This will
       make a drying chamber a little more than 30cm deep, which should
       be plenty for the most bulky grains, such as unshelled maize.
    *  Smooth any rough spots on the tops of the walls, so no bumps or
       loose pieces will be knocked into the dryer when it is in use.
9.   Build a chimney.
    *  Build a chimney
       up against the back
       wall of the dryer.
       Center it on the smoke
       outlet hole cut in the
       end of the back barrel.

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    *  You can use mudblocks the
       same size as in the dryer
       walls, and mortar.   Position
       the 20cm edges vertically.   This
       will give about a 12 x 12cm smokehole
       in the center, which is large enough to allow easy smoke escape,
       but small enough to keep down heat loss from the barrels.
    *  Leave a space in the chimney wall against the hole in the barrel
       end.  It will start after two layers of blocks and be about two
       layers high.   Fill in irregular-size spaces in the brickwork with
       cut blocks or mortar.   Center a full-size block over top of the
       space you have made.   Continue laying blocks until the chimney
       rises at least 1/2 meter above the tops of the dryer walls.
       This will keep smoke out of the drying grain.
    *  Make sure the chimney is sealed and free of cracks, so there is
       only one way for smoke to go:   through the hole in the barrel end
       and out the top of the chimney hole.

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1.   A shelter over the dryer will protect it and drying grain from rains.
    Build an open-sided one to overhang the dryer at least 1/2m on each
    side, and more on one side if you wish to have room for storing fuel,
    a work area, etc.
2.   Gather dry wood, maize cobs or other fuel before drying begins.
3.   Build the fire in the first barrel or mid-way into the second barrel.
4.   Prop one of the cut-off barrel tops against the front opening into
    the barrels on a block or a rock to adjust a good draft for the fire.
    A piece of a barrel top can also be placed part-way over the top of
    the chimney to give you more control of the draft.
5.   Watch and control the fire at all times during drying.  Do not dry
    with too large a fire:   you may kill or scorch the grain.   A medium
    size fire will give the best distribution of heat.
6.   If you have trouble getting enough heat, in the Simple Dryer you may
    try partly covering the side vents to get a better draft up around
    the barrels.
7.   You can modify the dryers by installing a fan or fans to push a
    steady flow of air up around the barrels and through the drying
    grain.  The resulting larger volume of less-hot air will dry the
    grain faster and with little danger of overheating.
8.   The dryers will take some time to reach operating temperature
    while the walls are heating.   Continue drying operations day and
    night to make best use of the heat built up in the dryer.  Load
    it with a fresh batch as soon as the one before is dry.
9.   Limit the drying temperature for food grains to 50-55 [degrees] C.  The
    bottom layer of grain should not be too hot to hold in your bare
    hands.  Grains for livestock feed may be dried at higher temperatures.
    Do not dry rice, beans or any grain to be used for seed in these
    dryers -- unless you install fans, and even then proceed cautiously.
    These grains must not be heated to more than 45 [degrees] C.
10.   Do not stir the drying grain.   Grain in the top layers receives
     moisture passed up from the warmer grain at the bottom, and gradually
     releases it as drying is completed.   If you stir these wetter kernels
     down again, they will re-wet the drier kernels that got stirred up
     to the top -- and drying will take longer.  Stir only to release
     the heat if overheating occurs.
11.   Dry grain until the moisture content is about 12%.  Grain is dry
     when a kernel is hard and breaks between your teeth with a sharp
12.   Load small grain such as millet and sorghum in a layer 5-8cm deep.
     Shelled maize and other grains may be loaded up to 10cm, groundnuts
     up to 20cm, and maize on the cobs up to 30cm.
13.   Maize may take one to two days to dry.
14.   Do not let dirt build up in the dryer.   Do not let the air vents that
     let air up around the barrels get clogged.  Keep the area clean.
15.   Check for rust holes in the barrels and for cracks in the joints.
     Replace badly rusted barrels and re-seal cracked joints.  Smoke leaking
     into the drying grain will discolor it and change its taste and smell.
16.   If you need to get up on the dryer floor while loading or unloading
     grain, avoid tearing the screen or mats -- do not stand in the spaces
     between the log supports.
16.   If one of the logs supporting the screen in the Simple Barrel Dryer
     becomes weak or rotted, you will be able to replace it by chipping
     some of the mortar away from each end, and pulling or knocking it
     out.  Slide in a new log and mortar the spaces around the ends.
                       THE PIT OIL BARREL DRYER
This dryer is based on a plan prepared in 1974 by American Peace Corps
Volunteers in Benin, West Africa.  It is called the Oil Barrel Dryer
simply because it is made from oil barrels.  It actually has received
different names depending upon the country where it was used.  The
first oil barrel dryer was built in Samoa to dry coconut meat.  Since
then, this dryer has been built and tested in a number of countries,
including Nigeria and Benin.  The dryer also is known as the Low Cost
Bush Dryer and the Brooks Dryer.
Proven advantages of the Oil Barrel Dryer:
           *  It is useful in areas where grain must be harvested in
              rainy weather.
           *  Maize on the cob can be dried without long drying in cribs
              and use of contact insecticides.
           *  Construction materials are easy to find in most places.
           *  Farmers can build the dryer with little
              assistance or supervision.
           *  It dries a lot of grain in a short time.
           *  Grain can be harvested earlier.  Because there is less
              drying time in the field, there is less danger of insect
              and rodent damage.
Possible disadvantages (depending upon area or situation):
           *  It is a better dryer for a group of farmers than it is for
              one farmer.   One farmer would not need it very much during
              a year.   Sharing by a group of farmers means more use and
              less expense to each farmer in building.
           *  The fuel used in this dryer is often firewood; sometimes
              maize cobs also are burned.   Firewood is becoming harder
              to get and more expensive in many places.
           *  There is no fan included in this plan to force air through
              the heating chamber and the grain bed.  Small gas motors
              needed to drive fans often are very expensive.
           *  It should not be used for grain which will be used for
           *  It would be worthwhile to find other economical natural
              fuels (like maize cobs).
           *  Banco construction (hand-rammed earth) works only where
              there is a high clay content in the soil.
Fans placed to drive the warmed air around the outside of the barrels up
through the drying grain would increase the efficiency of the dryer.   It
will be necessary to find a suitable power source for the fans.  In areas
where there are many small motor bikes, it might be possible to construct
a power drive made from a motor bike which permits temporary hook-up and
easy detachment of the bike as a power source.
The dryer is made of hand-rammed earth, known in different areas as banco,
terre de barre, adobe, etc.  The maize or other grain is placed on a
screened drying floor.  This floor is placed above a firebox made of three
220 litre metal oil drums joined together end to end.
You may substitute an available local material that will be as strong and
resistant to wear and heat as the banco, such as burned brick.  Sandcrete
(cement and sand) or concrete blocks will crack with the heat.  If
banco is already used for construction in your area, the same high-clay
content soil will work well for the dryer.  You may mix in cement with
low-clay soil to allow you to build the earthen walls.

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Tools and Materials
          *  3 oil barrels, 220 litres each
          *  [9m.sup.2] chicken wire or other screen, or a combination of
             screen and woven mats
          *  Iron or steel "re-rod" (reinforcing armature) for lintels.
             6mm diameter, 6m long
          *  Materials for concrete:  25kg cement
                                      1/2 barrel sand
                                      1/4 barrel gravel
          *  Heavy wire, about 2m
          *  Thin wire, about 15m
          *  10 logs, 8-10cm diameter; 2, 15m long
          *  2 strips of small mesh screen, each about 180cm
             long, and a few cm wide.
          *  Digging tools
1.   Select a site.
       *  Find a place for the dryer which is high and well-drained.
          If you dig too near a tree, roots will get in your way and you
          may damage the tree.   If you are in a swampy or drainage area,
          water will get into the dryer and wear away the walls.
2.   Make 2 lintels.
       *  The lintels are concrete horizontal slabs which will support
          the weight of the walls over the barrels.
       *  Make two forms out of boards or bricks.  Line them with paper.
          The forms should each make a finished lintel which measures
          120cm x 30cm x 8cm.
       *  Cut the re-rod into 6 equal pieces each measuring 1m long.
       *  Mix concrete in this proportion:  1 part cement
                                            2 parts sand
                                            3 parts gravel.
       *  Mix sand and cement thoroughly first, then mix in gravel.   Then
          add just enough water to make the concrete thick and smooth,
          but not watery.
       *  Pour concrete into the forms up to a level of 4cm and tamp
       *  Lay 3 pieces of 1m re-rod on top of the 4cm of concrete in
          each form.   Space them evenly, with the outside pieces about
          3cm from the edge.
       *  Finish pouring concrete into the forms.  Tamp firmly and level
          off the top surfaces.
       *  Cover them and keep them out of the sun or cover with grass.
          Keep them damp for about 7 days by sprinkling three times
          a day.   This slow drying cures the concrete to its greatest
3.   Stake out the drying chamber and stoking pit.
    *  Stake out the drying chamber, as shown, on the site you have chosen.
       It will be 2,80m x 3m.
    *  Make sure the dryer chimney is staked out downwind of the
       prevailing wind during the season when the dryer will be used
       most.  This is important -- it keeps the smoke from blowing
       back into the drying grain.
    *  Stake out the stoking pit against the upwind 2,80m side of the
       drying area.   Make the stoking pit 2m x 2,lm.  One of the 2,lm
       sides should be right next to the upwind 2,8m side of the drying
       chamber area.

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4.   Dig top soil out of the staked areas.
    *  Dig the staked out areas to a depth where you come to hardpacked
       earth that will make a good foundation.  We will use
       30cm in this plan.   Pile all top soil to one side so it will
       not get mixed with the banco when it is later wetted and used
       to construct the walls.

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5.   Dig a trench in the center of the staked out area.
    *  Dig a trench centered in the middle of the drying area 70cm
       wide and 140cm deep -- from ground level.  It should extend
       4.80cm from the chimney end of the drying area.  This will
       leave 20cm un-dug at the opposite end for a retaining wall
       for the stoking pit.
    *  Keep the dirt you remove separate from the top soil you
       removed before.

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6.   Make cut-outs for the lintels.
    *  Mark points at 2,70m and 3m from the chimney end on both sides
       of the trench.
    *  Remove the soil between these marks, and extending from the edge
       of the trench to a distance 30cm back.  Dig it down 40cm.   This
       will place the bottom surface 70cm up from the trench floor.
    *  Make two more slots up against the chimney end.   They should
       be 30cm wide, 30cm long and dug down 35cm, or until the bottom
       of the slot is 75cm up from the trench floor.

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7.   Make cut-outs for the chimney.
    *  The chimney hole should be dug into the soil at the back wall
       of the drying area.   Centered at the end of the drying area,
       dig out an area 30cm wide, which extends back 30cm beyond the
       drying area to a depth of 30cm below the ground level.
    *  Also centered at this end of the drying area, dig another area
       15cm wide, which extends 15cm back.  This channel will extend
       below the hole just completed until it is 50cm from the trench

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8.   Place the lintels.
    *  Lay a 5cm layer of banco in each of the four lintel slots.
       Lower the lintels into place.   Make sure they are level,
       and square with the side walls of the dryer.

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9.   Build the dryer walls.
    *  Make the front and back walls -- over the lintels -- 30cm thick.
    *  Build the side walls up from the floor of the original 30cm deep
       pit that you have dug out.   Make them 45cm thick until they
       reach a height of 90cm above the base of the front lintel.  At
       this point reduce their thickness to 30cm, leaving a 15cm wide
       ledge on the inside of each side wall.  This ledge will support
       logs for the drying floor.
    *  The height you may build the walls in one day will depend on
       the quality and consistency of the banco.
    *  Before the walls are too high, remove some of the dirt between
       each side of the oil barrel trench and the side walls.  Make
       a slope on each side of about 45 [degrees] starting at the inside edge
       of the base of each side wall and extending down to meet the
       sides of the barrel trench about 40cm above the floor of the
    *  Embed a strip of chicken wire, or other wire mesh you have chosen
       to use, into each of the walls, 10cm above the 15cm ledge you
       have made.   Each of the strips is 20cm wide and is as long as the
       wall it is placed in.   10cm of the wire should stick out flat
       into the drying area.   Later these strips will attach to the drying
       floor screen.
Continue the front, back and side walls until they rise 40cm
above the wire strips.  The top of the finished dryer walls
will be 75cm above ground level.

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10.   Build a retaining wall around the stoking pit.
     *  The retaining wall protects against erosion and will keep
        dirt and trash from falling into the pit.
     *  Build the retaining wall up from the floor of the original
        30cm deep pit that you have dug out.  Build it on three sides
        of the stoking pit area.   The fourth side is spanned by the
        front wall of the drying area.
     *  Make it 20cm thick.  The front wall of
        the stoking pit will fit exactly on
        the 20cm ledge you left at the front
        end of the 140cm deep trench that
        extends down the center of the dryer
        and stoking pit.

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     *  Build all three sides 50cm up from
        their base.   This will bring them
        20cm above ground level.
11.   Build the chimney.
    *  Build the chimney walls out of
       banco up from the bottom of the
       larger, top hole you have dug
       out at the end of the dryer.
       The inside faces of the chimney
       walls should be flush with the
       sides of the lower, smaller
       hole that is dug into the    
       bottom of the top hole.

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    *  Extend the chimney 20cm higher
       than the top of the back dryer
       wall.  As you build upwards,
       gradually narrow the inside
       passage of the chimney until
       it measures about 10cm x 10cm
       at the top.   This will help
       reduce heat loss.
12.   Finish the stoking pit.

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     *  You may excavate any dirt that is left in the stoking pit
        so that the dirt walls in the front and opposite the stairs
        are flush with the inside surfaces of the retaining wall which
        rests on them.
     *  Cut stairs in the dirt next to the stoking pit.   Make four equal
        steps each 30cm high and 40cm across.
     *  Leave a ledge 30cm thick between the lowest step and the front
        dryer wall, to help brace the dryer wall.
13.   Assemble and place the firebox barrels.
     *  Cut both ends from two 220 litre barrels.
     *  Cut one end from a third barrel.  Cut a hole 20-30cm across
        near the edge of the other end of this barrel.  This will be
        placed up against the opening at the bottom of the chimney.
     *  Punch four evenly spaced holes around the rim of each barrel
        where it will join another barrel.
     *  Join the three barrels together by tying pieces of heavy wire
        through the punched holes.
     *  Locate the barrel assembly in the trench with the small hole in
        the end of the third barrel placed up against the bottom
        opening of the chimney.
     *  Support the barrels on bricks about 10cm above the bottom of
        the trench.   Incline them slightly upwards towards the chimney
        for easier smoke escape.   This will allow air to circulate all
        around the barrels and will also prevent rusting.

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     *  Seal the joints between the barrels by placing a strip of
        screening around them and plastering with a mixture of mortar
        (1 part cement to 8 parts sand).
     *  Close the trench around the barrel assembly ends under the lintels
        with banco.   Make sure you seal completely around the barrel at
        the chimney end to prevent any smoke "backflow".  Close the
        front end of the barrel assembly only around the top of the
        barrel to let cool air enter the drying chamber -- this cool
        air is warmed and will rise up through the drying floor and   

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     *  Test the seals at the joints.  Light a smoky fire and see if
        smoke escapes into the drying chamber.  Do not let it burn long
        enough to dry the mortar on the joints.  Keep the mortar damp
        until it is hard.
14.   Assemble the drying floor supports.
     *  Use 10 logs of solid wood.  The logs should be 8-10cm in
        diameter and 2.15m long.
     *  Space the logs evenly across the drying chamber from one end
        to the other.   The log ends will rest on the 15cm ledges in
        the side walls.   Resting the logs on the ledges instead of
        fixing them in place means they can be replaced more easily
        if they weaken.

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15.   Place and fasten screening on top of the log supports.
     *  Stretch screening across the logs and attach it to the 10cm
        of wire mesh sticking out from each wall.  Make the
        screening longer than the inside length of the chamber because
        the weight of grain will make the screen sag between the logs.
        Overlap all sections 5 or 10cm and fasten together with thin
     *  Small mesh screen is best.  But chicken wire can be used.
        Place straw mats over chicken wire, or other large-hole screen,
        to keep grain from falling through the holes.  Some kinds of
        woven mats are very strong.   These can be used in place of
        screening.   Fasten woven mats to wire mesh strips embedded
        in the walls the same as you would metal screen.

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                       PHILIPPINES RICE DRYER
Scientists working in the Philippines and other rice-growing countries have
discovered new kinds of rice seed which grow more quickly.  This means the
crop is ready for harvest sooner; often a farmer can plant and harvest two
crops in the time it used to take for one crop.
However, because the growing time is shorter, the rice is ready for harvest
during the rainy season.  Before, the rice would not be ready until the rains
were finished.   The farmer must harvest, but he cannot dry his grain outside
in the sun.   The problem he faces is simple, and it is a problem for
farmers all over the world who must harvest during wet or humid times:
how to get the grain dry before it is ruined by insects and molds.
Scientists working at the University of the Philippines and the International
Rice Research Institute in Manila, Philippines, have come up with answers.
They have designed two versions of a dryer model they feel is relatively
inexpensive, simple to make, easy to operate and maintain.  We call it
here the Philippines Rice Dryer.  Each version of this dryer will be discussed
There are advantages and disadvantages to the use of this dryer by small
farmers.   Advantages are:
       *  It can be used in the rainy season.
       *  It uses less fuel than the oil barrel dryer because the
          fan forces air through the grain and decreases drying
       *  It requires construction using relatively sophisticated
          materials, tools, and skilled labor.
       *  It burns fuel which can be costly.
       *  It requires finding and paying for special machinery.
       *  It is practical only for wealthier farmers or a group
          of farmers.

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The first rice dryer is from the Grain Processing Program of the Department
of Agricultural Engineering at Los Banos, Philippines.  It has three main
parts:   a bin which holds the grain (placed on sheet metal with holes) over
a container of hot air (plenum); a fan to force air from the plenum through
the grain; and a burner to heat the drying air.
A brief description of the major parts of the Philippines Rice Dryer:
Grain holding bin
       *  Floor area is 1.8m x 3.6m.
       *  2cm plywood.
       *  5cm x 5cm lumber.
       *  Perforated sheet metal (sheet metal with holes).
       *  58cm fan adapted from truck radiator fan.
       *  Pushes 8.5 cubic meters per minute of air against a total
          pressure of 2.5cm water column.
       *  Size of the blower is chosen to fit the size of the grain
       *  No stirring is necessary.
       *  Mount fan with flange bearings, sheet metal housing.
          Reinforce with angle bars.
       *  5 hp gasoline or diesel engine.
       *  V-belt and pulley.
       *  A power tiller which has an 8 hp engine can be used.
       *  43 [degrees] C recommended temperature so as not to damage milling
       *  Developed direct flame kerosene burner.  Consists of 3-part
          iron casing, needle valve between burner and housing, and
          a double shell sheet metal housing.  Uses 1.5 litres of fuel
          each hour.
Other items
       *  V-tube manometer to read air pressure at plenum and to
          set engine throttle.
       *  Dial thermometer to show drying air temperature.
      A.  Kerosene Burner
      B.  Fan and Engine
      C.  Grain Bin
      D.  Plenum
      E.  Perforated Metal Floor

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Notes on Operation of the Dryer
       *  It takes 2 men an hour to assemble the dryer.   This is the final
          putting together of the pieces.   This is the time it takes if
          the grain bin is already made and all the parts are ready to
       *  The dryer must be used under a shed to protect it and the grain
          from rain.
       *  The bin holds about 1700kg.
       *  The manometer is a guide to engine speed: a 2.5cm displacement
          of the water column shows the engine setting is correct.
       *  The temperature of the air for drying is adjusted by controlling
          the flame through the needle valve and by adjusting
          the distance between the burner housing and the fan intake.
       *  Drying continues until the top layer of grain is at 14%
          moisture.   (It will take about 8 hours of steady drying to
          bring moisture down from 26% to 14 or 13%.)
For detailed technical bulletins describing construction and use of the
Philippines Rice Dryer contact:
          The Project Director
          Training of Technicians for Grain Industries
          Department of Agricultural Engineering
          University of the Philippines at Los Banos
          Laguna, Philippines

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The IRRI Batch Dryer is different from the early University of the Philippines
model in 2 important ways:
       1.  It can use a self-feeding rice hull burner instead of gas
           or kerosene.   This burner uses 3-4kgs of rice hulls per hour
           or 25kg per ton of rice dried.   One ton of rice contains 200kg
           of rice hulls, so there are plenty of hulls to feed the burner.
           In other words, one ton of paddy produces enough hulls to dry
           that same ton of rice kernels.
       2.  The fan used is a 47cm diameter vane-axial type rather than
           varying sizes and models of truck radiator plans.  The use of
           a standard fan allows the operator to fix standard drying times.
Other notes on the IRRI Batch Dryer
       *  Drying capacity is 1 metric ton.  It can dry this amount of
          paddy rice in 4-6 hours depending upon the initial moisture
          content of the grain.
       *  The oil burner uses a 3 hp gasoline engine (a 2 hp electric
          motor can be added to drive the blower).  A kerosene burner
          is installed in the air duct.
       *  The rice hull furnace has a steel frame and is lined with
          fire bricks.   It consists of a combustion chamber and an
          ash trap.
       *  Either heating arrangement can raise the drying air temperature
          from 29 to 43 [degrees] C at an air flow rate of 30-35 cubic meters
          of air/min/[m.sup.3] of grain.
       *  Fuel consumption for the oil burner is 0.75 litres per hour
          for the gasoline engine and 2.0 litres per hour for the
          kerosene burner.
       *  The rice hull furnace burns 3 to 4kg per hour of rice hulls.
 This dryer, like the Los Banos Dryer, may be hard to put together:  in
 some areas the materials may be expensive; in other places the equipment
 is hard to find.   These facts make it hard for many small farmers to use
 such a dryer.   A group of farmers, however, would be more likely to be
 able to use such a dryer cooperatively and profitably.  And the dryer can
 be manufactured locally.
 For more information and detailed engineering drawings, contact:
          Agricultural Engineering Department
          The International Rice Research Institute
          P. 0. Box 933
          Manila, Philippines
                              SOLAR DRYERS
                        PART ONE:  CONSTRUCTION
The following plans are based upon a construction manual written by James
McDowell as a result of his experiences at the Caribbean Food and Nutrition
Institute in Trinidad.  VITA technical artist George C. Clark has
provided added illustrations, as well as a simplification of the building
procedure of the Model #1 dryer.
McDowell's plans in turn were developed from the ideas and principles
of Dr. J. Lawand and associates of the Brace Research Institute, McGill
University, Quebec, Canada.  Now with UNICEF in Kenya, McDowell has used
the dryer to dry grain from 25% to under 12% moisture in one day or less.
Solar Dryers have several possible advantages
     *  There are no fuel costs.
     *  Sun drying time is reduced because the heat of the sun is
        made stronger by covering the drying grain with a double
        layer of clear plastic film.
     *  They can be used to dry other crops -- copra, cassava,
        fruits, vegetables.
There can be disadvantages also
     *  Temperatures in the dryer may build up to 65-80 [degrees] C.   This
        means that grains such as rice, which crack at temperatures
        above 50 [degrees] C, or seed grains (which can be dried at
        temperatures no higher than 40-45 [degrees] C) can be damaged.  A
        farmer has to watch the grain carefully, and, if no
        thermometer is available, will have to learn by trial
        and error.
     *  Dryers are most useful only at certain hours of the day
        and would be of limited use during long periods of
        rainfall or very cloudy weather.
The dryer models here were designed and tested for drying cereal grains,
root crops, fruits, and vegetables.  The dryer holds 8 to 11kg for each
square meter of drying floor.  Dryers of the size presented here will dry
18-24kg each day.  If a farmer wants to dry more grain, he will have to
make a larger dryer or build several dryers.
Instructions and sketches for three versions of a Solar dryer are given
in the following pages.  These dryers can be made from whatever materials
are most available locally.  The dimensions given here are for general
guidance.   You can change the length, width, or depth of these dryers
without affecting their efficiency.
The sketches for Models 1 and 2 are based on a useful, practical working
size of 2m in length, 1m in width, and 23-30cm overall depth.   But changes
in area can be made to suit local conditions, and dimensions of materials
available.   IMPORTANT:  The only dimension which should be followed as
closely as possible is the thickness of insulation on the Model 1 box-type
dryer.   Where wood shavings, wood wool, dried grass, leaves, or similar
material are being used, a minimum thickness of 5cm should be used.   Also,
the internal depth of Models 1 and 2 should not be less than 15cm.
                       MODEL # 1 SOLAR DRYER
This model consists of an outer box and an inner box.  The inner box
is at least 10cm less in length and width, and at least 5cm less in depth
than the outer box.  The space between the boxes is packed with suitable
insulating material.
Lower air holes are drilled through the bottom of the boxes (and through
spacer boards fitted in the insulation space for this purpose).  Slots
are cut in the upper edges of the sides of the box to provide upper air
outlets.   The dryer is supported about 15cm above the ground on four legs
(which also form the main corner members for the box)

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Tools and Materials
     *  Hammer, screwdriver, tri-square, saw, brace, and 2.5cm
        wood drill, 2cm wood chisel.
     *  Wooden planking or plywood for Sides, ends, and bottom
        of boxes.  Use wood from old packing cases if it is
     *  Lengths of timber:
             4 pieces 5 x 10cm for legs
             4 pieces 5 x 5 cm for legs
            13 pieces 5 x 5 cm for the side, end, and bottom
                                              spacer strips.
     *  Insulating material:  wood wool, dried grass or leaves,
                              coir fibre, etc.
     *  Nails and screwnails of appropriate size.
     *  Flat or matt-black paint or other suitable black staining
        material, e.g., charcoal, that is not shiny or glossy.
Build the Inner Box
     *  Check all measurements and markings on the wood before cutting.
     *  Cut side and end pieces.  These can be one piece of wood, or
        you can join narrower planks together to make a box about the
        right size.
     *  Put the pieces together.  Make sure the nails are completely
        hammered into the wood.

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     *  Cut and nail the leg pieces to the corners as shown.

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<FIGURE 100>
<FIGURE 101>
<FIGURE 102>
<FIGURE 103>
     *  Make the air outlet slots.
        -  Mark the position of the air outlet slots on the
           upper sides.
        -  Cut out the slots in any of the three ways
     *  Paint or stain the inside of the box with a dark color.
        A flat black is good.   It is a good idea to put a wood
        preservative on the outside if you have it.  Then paint
        the outside with gloss paint or marine varnish -- if
        you can find them.
The same cover is used for both dryers.  It consists of a rectangular
wooden frame with a central ridge piece.  It is covered with a double
layer of polyethylene film
<FIGURE 104>

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Tools and Materials
     *  Saw (preferably tenon saw), screw-driver, sharp knife or
        scissors, tri square, marking gauge.
     *  Lengths of timber:  about 5cm x 2cm.
     *  Transparent plastic (polyethylene) film (preferably .127mm
        or heavier).
     *  Screws (1.6cm x 8s C.S.).
     *  Blued tacks (1cm) or large office stapler.
Make the frame so that its length and width are each 8cm greater than
the box to be covered.  The cover will overlap the dryer box by about
4cm in each direction.
1.   Make the Frame
     *  Cut the pieces for the frame to the right lengths.
     *  Put them together as shown.
<FIGURE 105>

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     *  Dry the frame in the hot sun before putting on the plastic.
2.   Put the Lower Plastic Sheet on the Frame
     *  Put the cover on while the wood is still warm and at a
        time when humidity is low.   These precautions are necessary
        to prevent condensation (fogging) between the
        layers of polyethylene.
     *  Cut a piece of plastic sheet for covering the lower
        side of the frame so that it is 8cm wider and 8cm
        longer than the frame.
     *  Turn the frame upside down and lay
        the plastic sheet in place.   Fold
        one side of the polyethylene back
        on itself to form a triple layer
        seam 2cm wide.
<FIGURE 106>

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     *  Start at the middle of the frame and work toward both ends.
        Stretch the plastic lightly but firmly lengthwise.  Tack
        or staple through the seam at 8cm intervals to fasten
        this edge of the polyethylene to the frame.  DO NOT OVER-STRETCH
     *  Repeat this process at the other side of the frame.
        Stretch the polyethylene across the frame while tacking
        or stapling.
     *  Fold similar seams at each end.  Tack the ends of the
        sheet to the frame.   Tuck the plastic neatly at each
        corner.   Fasten firmly in place.
3 Put the Upper Plastic Sheet on the Frame
     *  Cut a piece of polyethylene sheet for covering the upper
        side.  This sheet, when placed over the frame, should be
        10cm wider and 10cm longer than the frame.  Turn the
        frame upside down and, making a triple fold seam as
        before, tack or staple one edge to one side of the frame
        so that the seam overlaps the triple seam of the lower
<FIGURE 107>

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     *  Stretch the polyethylene over the ridge and around to the
        lower edge of the other side member.  Make a folded seam
        and tack or staple in place as before.
     *  Stretch the polyethylene over one end of the frame, fold
        and tack as before, cutting away any extra material resulting
        from the slope from ridge to side member.  Tuck
        the corners of the sheet in neatly, and tack firmly in
        place.   Repeat for the other end of the frame.
4.   Attach the Covers to the Dryers
     *  The covers do not weigh much and are likely to blow off the
        dryers even in a light wind.   The cover can be kept on by
        fastening hooks of stiff wire to each corner of the cover
        and swinging these hooks into place around nails or pegs
        fixed in the sides of the dryer.
     *  Or, fasten lengths of strong twine or cord to one side of
        the dryer, draw them tightly across the cover, and tie
        them to nails or pegs on the other side.
<FIGURE 108>

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This is a simple wooden frame with fine wire mesh stapled to its underside.
Two support runners are nailed to the underside (over the edge
of the wire mesh).  If necessary, two small pieces of wood may be tacked
over the edges of the wire mesh to hold it in place at the ends.  However,
folding the edges of the mesh over upon itself before stapling may be
all that is needed.
Make two trays, each slightly smaller than 1m x 1m so that it will fit
the dryer box well.  It is a good idea to make two trays because they
are easier to handle than one large tray.  Also, using two trays means
that grains at two different moisture levels can be dried at the same
Simpler trays may be made from local materials.  Papyrus reed matting,
or a frame with slats of reed or split bamboo, for example, make an
excellent support on which material can be dried.  Coarse hessian
sacking material, or open weave grass or fibre matting stretched on
a frame also can be used.
               MODEL #2 SOLAR DRYER
This dryer also is for a 2m x 1m dryer.  But it is not portable like the
Model #1 Solar Dryer.  It is built on a permanent location and is made
with clay bricks, or similar material.  Bricks composed of local earth
and cement and compressed by a CINVA-RAM work very well.  If hollow
bricks are used, the hollows should be packed with dried grass, coir
fibre, or other insulating material.
<FIGURE 109>

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Choose a Site
A good place for the Solar Dryer will be
     *  high ground which is flat and level.  Make sure the location
        is well drained.
     *  out in the open -- not shaded by trees or buildings.
     *  exposed to the prevailing wind.  The end of the dryer
        should be facing the prevailing wind.
Tools and Materials
     *  Large knife, axe, or machete
     *  Coping saw or wood rasp
     *  2cm chisel
     *  Clay bricks or bricks made from similar material
     *  Mortar or clay for laying bricks
     *  Thick bamboo (6 to 7.5cm diameter)
1.   Prepare Site
     *  Lay out dryer size by building up the corner blocks.
<FIGURE 110>

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     *  Prepare a floor of hard-packed earth or concrete mortar.
     *  Dig a drainage trench around the dryer to protect it from
        heavy rain.   The trench should be 23-30cm wide and 23-30cm
2.   Prepare Bamboo Pipes
     *  Choose bamboo of even thickness with as few joints as
     *  Cut bamboo to the same length as the width of the dryer.
     *  Then prepare the pipes as follows:
<FIGURE 111>

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     *  Cut holes, about 4cm in diameter, in each pipe.   Holes
        can be made by using one of these methods:
<FIGURE 112>

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3.   Finish the Walls
     *  Place the bamboo pipes in position in the second layer.
        Cut the blocks short as necessary to fit in the bamboo
<FIGURE 113>

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     *  Put down the third layer of bricks.
     *  Pack the holes around the bamboo with mortar or clay.
     *  Put down the top layer of bricks and cut out the air
        outlet slots or lay the top layer of bricks leaving
        one inch gaps as air-outlet holes spaced along the
        two sides.
<FIGURE 114>

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4.   Paint the Inside
     *  Paint the inside of the dryer a dark color.   Charcoal,
        mixed with clay and water may be a good coating.
5.   Construct Cover and Drying Trays as for Model #1
A Dual-Purpose Solar/Fuel-Heated Dryer
It is possible to build solar dryers which can work on solar heat for most
of the time, but which can, if necessary, be artifically heated during
periods of heavy clouding or rain.
A modification of the Model 2 dryer will allow for this dual-purpose
operation.   This modification consists of building-in a metal flue pipe
which runs through the length of the dryer.  This pipe carries the heat
from a firebox built at one end of the dryer.  When drying has to be done
in cloudy conditions, the fire can be lit to provide heat for drying.
<FIGURE 115>

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Either one large, say, 11cm diameter pipe, or a number of smaller pipes can
be used.   When using smaller pipes, difficulties in constructing a manifold
may arise.   But it may be possible to adapt an exhaust manifold from an
old gasoline or diesel engine for this purpose.
An increase of 7.6cm (or one brick) in height, should be sufficient.
The firebox may be built in clay or brick, or a section cut from an old
oil drum may be used for the purpose.
The base of the firebox must be at a lower level than the dryer.
     *  Make sure that this area is protected from any flooding which
        may occur during heavy rains.
The flue tube running through the dryer should slope upwards towards the
chimney to assist draught.
<FIGURE 116>

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  When using artificial heat, the movement of air through the dryer by
convection will operate as it does when solar heat is being used.   However,
depending upon the heat given by the fuel being used, it may be necessary
to close-off more of the upper ventilation ports.
     *  Make sure that the part of the flue pipe passing through the
        dryer is smoke-proof.   If it is not smoke-proof, smoke will
        flavor the foods being dried.   A damper should also be placed
        in the chimney. This damper must be kept closed when sun-drying
        is being carried out, or the flue pipe may exert a cooling effect.
     *  Make sure to site this modification so that the firebox end
        faces into the prevailing wind.   This will assist draught through
        the flue, and will also ensure that any sparks from the chimney
        are carried away from the polyethylene cover.
                       MODEL #3 SOLAR DRYER
This is a simple dryer.  It is not as efficient as the other two in
conditions where it is exposed to cooling winds, but it will provide
more efficient drying than direct exposure to the sun, and will also
protect the drying material from rain.  It is essentially a "sandwich"
Of two sheets of corrugated galvanized iron roofing material placed so
that they form a series of tubes.  The lower sheet is bedded in insulating
material to reduce loss of heat.  It is set in a sloping position
with one end raised about 15cm higher than the other.  This position
allows hot air to rise and escape at the upper end, creating a draught of
air over the material being dried.  The material which is being dried is
placed in the hollows of the lower sheet.
There are a number of possible ways of siting and constructing this dryer.
It can be permanently sited or made portable.  Certain refinements can be
added to increase its efficiency.  For this reason the construction of a
simple portable model will be described first; possible modifications will
be described later.
The Portable Dryer
In this model, the corrugated sheets are fastened to a shallow wooden box
which contains a bed of insulating material.  The box will be about 10cm
high and 80cm wide.  The dimensions of the box will depend on the final
size of the prepared corrugated sheets, so the sheets are prepared first.
Tools and Materials
     *  Hammer, saw, tri-square, wood chisel, pliers
     *  2 sheets corrugated galvanized iron
     *  Timber for bottom and sides of box
     *  Nails or coat-hanger wire
     *  Black paint
1.   Prepare the Sheets
     *  When purchased, the sheets will be packed closely together.
        Turn the upper sheet 180 [degrees] so that the sheets are on top
        of each other.   The upper sheet will tend to slip sideways
        and will not remain evenly positioned.
     *  Mark a line along the edges of
        each sheet about 1cm from the        
        edge.  Using pliers, and moving      
        gradually along the sheet, bend      
        the edges down to form flanges       
        which are level with the plane       
        of the sheet.   Once the edges         
        have been bent into position,        
        lay each flange along the edge       
        of a piece of wood and beat with     
        a hammer until it is flat and        
        smooth.   The sheets will now         
        lie properly together in the         
        correct position.                    
<FIGURE 117>

51ap119a.gif (486x486)

2.   Hinge the Sheets
     *  The sheets must be held together so they can be easily positioned
        during future use.   This is done using wire rings.
     *  Wind a piece of suitable wire spirally around a 1cm diameter
        form (e.g., the handle of a wooden spoon) to form 6 loops.
        Remove from the form and pull the ends of the wire so that
        it forms a loose spiral.   Cut this spiral with the pliers
        so as to form a number of rings with overlapping ends.
<FIGURE 118>

51ap119b.gif (486x486)

     *  Punch five holes through the flanges at one edge of each
        sheet, using a nail and a hammer.   These holes should be
        positioned as follows:   one hole about 7.5cm from each end
        of the flange, one hole in the centre of the flange, and
        two holes midway between these holes.
        Pass the wire rings through these holes and close the
        rings by pressing the ends together.  This effectively
        hinges the sheets together and allows accurate positioning.
3.   Prepare the Dryer Box
     *  The shallow support and insulating box can now be constructed
        to fit the dimensions of the lower sheet of corrugated iron:
        cut slots in the upper edges of the one side of this box to
        provide space for the hinge rings.
<FIGURE 119>

51ap120.gif (486x486)

     *  Pack the box with insulating material, e.g., wood wool, dried
        grass or leaves, or other similar material.
     *  Place the corrugated sheets in position and fasten the lower
        sheet to the frame by nailing through the flanges along each
        edge and through the points where the sheet contacts the ends
        of the box and the central support batten.
     *  Close the openings at each end between the corrugations of
        the sheet and the wooden frame by filling with cement, plaster
        or clay.
4.   Paint the Dryer
     *  Paint the upper surface of the top sheet with a flat black
        paint.   Using a suitable primer to be sure of sticking to
        the metal.
     *  Treat the wood of the box with preservative, or paint with
        gloss paint if available.
     *  Site with the length of the dryer in a north-south
        direction, preferably in a position where it is sheltered
        from the wind.
     *  Raise one end so that it is 15cm higher than the other.
     *  Make sure the rays of the sun strike the upper sheet as
        directly as possible.   (The end to be raised will depend
        on the latitude and season of the year.  For example, in
        latitudes more than 5 degrees north of the equator, the
        northern end of the dryer should be raised in winter
        and the southern end in summer.)
Protecting from Rain
There is a risk that driving rain may enter the upper end of the dryer
and wet the contents.  It is thus necessary to fit a shelter plate to the
upper sheet at this end of the dryer.
     *  Nail a wooden batten across one end of the upper surface
        of the top sheet.
     *  Nail to this wood a strip of metal which is the full width
        of the sheet, and which will jut out about 15cm beyond the
        end of the dryer.   This metal can then be bent downwards
        in a gentle curve at its outer edge so as to shelter the
        open end of the dryer.
<FIGURE 120>

51ap121.gif (600x600)

Fitting a Polyethylene Cover
The efficiency of the Model 3 dryer can be greatly increased by fitting
a polyethylene cover over the top metal sheet.  The plastic creates an
insulating air space between the polyethylene and the corrugated sheet.
     *  Build a simple wooden frame over the top sheet using two
        vertically placed battens along each of the flanges, and
        two joining battens across each end of the sheet.
<FIGURE 121>

51ap122.gif (486x486)

     *  Fill the spaces between the corrugations and the end battens
        with plaster, clay, or cement.   Stretch a single sheet of polyethylene
        over the frame.   Tack or staple the sheet in place.
     *  Keep the slots in the side piece of the frame (necessary to
        accommodate the hinge rings) as small as possible.  They should
        only be cut enough to allow clearance for the rings.
The polyethylene cover will protect the upper corrugated sheet from the
cooling effects of wind and rain.  It also insulates the dryer so that
higher drying temperatures are possible.
The dryer described above can be permanently sited on a clay platform,
thus avoiding the need to construct a support and the lower insulating
box.   The clay platform will provide insulation.  This type is built as
     *  Flange the sheets and hinge together as described for the
        portable dryer.
     *  Nail wooden battens about 4cm x 2cm across the lower side
        of the lower sheet at each end and at the middle, to
        provide rigidity.
<FIGURE 122>

51ap123.gif (486x486)

        Construct a simple sloping clay platform the size of the
        lower sheet and 15cm above ground level at one end and
        30cm above ground level at the other.  Mix large quantities
        of dried grass or leaves with the clay.
        While the clay is still wet and soft, bed the lower sheet
        in position so that the clay moulds to the corrugations
        of the sheet.   Allow the clay to harden.
<FIGURE 123>

51ap124a.gif (486x486)

CAUTION:   Make sure to site this dryer in a position which will give the
                  most effective exposure to the sun at the time of year when
                  the most drying is being done.

51ap124b.gif (486x486)

General Instructions
Start drying as early as possible in the day to get maximum exposure to
the sun.   Once material has been placed in the dryer and the cover placed
in position, do not lift the cover until drying is completed for the day:
taking the cover off will allow a lot of heat to leave the dryer.
Brush the dryer out daily to get out dust, and to remove any pieces of
dried material spilled from drying trays.
Keep the drying trays clean; wash them often.
Temperature Control
Control the temperature inside the dryer by opening or closing the upper
air outlets.   Temperature may be measured by putting a thermometer in one
of the upper air outlets.  When doing this, shade the thermometer from
direct sunlight by inserting a card beneath the cover.  Temperatures
measured in this way will be the maximum (not necessarily the average)
internal temperature.
Or, temperatures at the level of the drying material may be measured
by drilling a hole through the side of the dryer and inserting a thermometer.
Again, make sure that the bulb is shaded from direct sunlight.
Closing the upper ventilation outlets will increase internal temperatures.
However, if moisture begins to collect inside the dryer you must start
opening the outlets.
In cases where opening all the upper outlets still results in temperatures
which are too high for the material being dried, additional outlets should
be cut in the upper edges of the sides.
Shade Drying
Some materials, particularly green vegetables, carrots, plantain and some
varieties of sweet potato, may lose color and Vitamin A during direct
exposure to sunlight.  For these materials, shade drying is useful (but
not completely necessary).
To do shade drying, fit sheets of thin metal immediately below the cover.
Paint the metal (galvanized sheet or beaten-out tin containers) black on
both sides.   The size of the metal sheet should be just less than the
internal length and width of the dryer.  Support the sheet on nails driven
into the inner sides and ends of the dryer.  Put the nails in not more than
half-an-inch below the upper edges of the sides.
Make sure the sheets do not touch the lower side of the polyethylene cover
(otherwise their heat may cause it to melt).  But the sheets should be
high enough so that hot air from beneath the sheet can still escape
through the upper air outlets.
When fitted properly, as described above, these sheets will send almost
all of the heat they receive to the air inside the dryer, and
the internal temperatures are similar to those made by sunlight.   Use of
metal shading sheets can, in fact, assist drying, since their presence
encourages more effective convection air movement through the dryer.
If fogging occurs during use, withdraw tacks or staples from a short
length at each end of the cover, open up the polyethylene to allow moisture
to escape while the dryer is in operation, and then refasten the
polyethylene in place.
"Storage" Heating
A simple modification to either the Model 1 or Model 2 dryers, which
will enhance efficiency of drying during periods of intermittent clouding
or rain, is the placing of a layer of dark-colored (or black-painted)
rough-surfaced stones in the bottom of the dryer.  These stones should be
egg sized or slightly larger.
During periods of sunshine, the stones will become heated.  Then when the
sun is covered by clouds, the stones maintain the internal temperature
by giving up heat to the air.
To make sure crops do well in storage, they should be carefully dried,
either "in the head" or after threshing, before they are placed in storage.
If dried "in the head," grains should be threshed before storage since
closely packed grain is less subject to insect attack.
Groundnuts can be dried either in the shell or after shelling.  Storage
in the shell provides protection against insect attack.
Shattering sesame may be harvested before pods are quite ripe and dried
in trays with very fine mesh bottoms.  It will then shatter in the dryer.
But since all the seeds will be retained, this method of dealing with
sesame has great advantages.
Threshed grains should be spread in a 1cm to 4cm deep layer on drying
trays of appropriate mesh size, so as to give a loading of about 7-10kg
per square meter.  For bulky material such as unthreshed finger millet
or sorghum, layers up to 7.5cm deep can be used.  For groundnuts in the
shell, layers may be up to 5cm deep.
For very small seeds, such as finger millet or sesame, trays with a very
fine mesh will be needed.  Mosquito netting or tightly stretched hessian
sacking would be appropriate.
                         Appendix A
This Appendix contains some examples of different ways of presenting
grain storage information.  The examples are from Asia, Africa, and
South America, thus highlighting the fact that good grain storage is
an important subject all over the world.
The traditional Botswana designs of mud cribs are
easy to build and the materials cost very little.  By
taking more care over some details during construction,
you can reduce the risk of insect damage to stored grain.
Issued by the Department of Agriculture, Information Service, Private Bag 27, Gaberones.
Choose a place where the ground is firm and well drained, because a crib full of grain is
  heavy and may sink into soft or wet ground.
Bring several large, smooth stones and bury them firmly in the ground to form a base.
Use strong, straight poles for the main crib supports and lay them on the stones.   Cut
  notches or fix pegs at the ends of these poles to prevent the floor poles from slipping.
Make a floor of mud and build up the mud walls.
  Reinforce the mud ceiling with poles.
<FIGURE 124>

51ap129.gif (600x600)

Make an outlet at the bottom of each compartment to permit easy removal of grain.   Use an
  empty coffee or dried milk tin with a lid of the press-in type.  First cut out the bottom.
  then build the tin into the wall at floor level.
Build the walls right up to the ceiling so that each compartment is completely separate
  and there is no chance of insects moving from one compartment to the next.
Plaster the inside walls and ceilings.  Insects hide in cracks and crevices and in the poles
  of the ceilings.   Therefore plaster the ceilings also, so that there is no gap between
  the walls and ceilings.
<FIGURE 125>

51ap130.gif (600x600)

Cover the completed mud crib with a thatch roof supported on separate poles.   Thatch
  should be thick and rain proof especially along the ridge.  The roof must also extend
  well beyond the crib so that rain cannot reach the mud walls, and the hot rays of the
  sun never shine on the crib.
The plug for filling the crib should be smeared over with mud to make the crib airtight
  and insect proof.   Grain is removed by opening the lid of the tin at the bottom of the
The crib should be repaired before each harvest.  Mend the thatch and re-plaster over
  cracks in the walls, floor and ceiling.
Thoroughly clean out the empty crib by brushing.  Do not keep old baskets, skins, sacks,
  etc. on top of the mud crib.   These things harbour the beetles that attack grain and it
  is easy for them to walk into the crib.
Make sure that new grain is always quite dry and has been winnowed or sieved before you
put it into a crib.  Never mix new grain with old grain remaining from the previous year.
To stop insects damaging your grain, admix Kopthion or Pyrethrum dust (1 packet of dust
to each 200 lb. of grain.)  These insecticides are preferred but the ash from cattle dung or
wood may be used.  Mix not less than one bucket of sieved ash with each 200 lb. of grain.
Examine the condition of your grain every 2 months by removing a sample and looking for
live insects.   If you find them, remove the grain, winnow it and admix Kopthion or pyrethrum
before returning it to the crib.
Grain intended for human consumption should be first sieved or winnowed and washed - especially
  if it has been treated with insecticide or ash.
If you would like further help, ask your Agricultural Demonstrator.
                 Printed by Government Printer Gaberones
                      HOW TO ....
                      PROTECT YOUR
                     GRAIN IN STORAGE
                       FROM DAMAGE
      Distributed through:
                     SAVE GRAIN CAMPAIGN
                      (Country Wide Programme)
                         DEPARTMENT OF FOOD,
                            NEW DELHI-1.
                     Apply the 5 Golden Rules:
           *  Dry and clean your grain before storing.
           *  Use dunnage to avoid moisture damage to grain
              stored in bags.
           *  Use domestic bins or improve your storage
           *  Fumigate with EDB ampoules to avoid insect
           *  Use anticoagulant for rat control.
<FIGURE 126>

51ap134.gif (600x600)

51ap135.gif (600x600)

51ap136.gif (600x600)

<FIGURE 127>
<FIGURE 128>
                       FOR ADVICE ON YOUR STORAGE
                         PROBLEMS AND TRAINING
                          CONTACT ANY OF THE       
                           FOLLOWING PLACES
                             IN PERSON OR
                               BY POST:
                           SAVE GRAIN CAMPAIGN
                            Department of Food
                          Ministry of Agriculture
                               Krishi Bhavan
                                New Delhi-l.
           Post Box No. 10                       Post Box No. 7823
           Hapur (U.P.)                          Bombay
           Post Box No. 509                      Post Box No. 22
           Patna (Bihar)                         Bapatla (A.P.)
          Post Box No. 158
          Ludhiana (Pb)
          Prepared by:
                        HAPUR (U.P)
<FIGURE 129>

51ap139.gif (486x486)

                          MINISTRY OF AGRICULTURE
                   Division of Stored Products-Extension
                       Managua, D.N., Nicaragua, C.A.
                       Preparado por:
                                      Ramiro Lopez
                                      Asistente de Extension de
                                      Productos Almacenados.
                       Revisado por:   Agro. Francisco Estrada
                                      Jefe de Extension de
                                      Productos Almacenados,
   Cada ano, durante el periodo comprendido entre la cosecha y el momento en que
el producto llega al consumidor, el exceso de humedad del grano, el ataque de
roedores, hongos, insectos y pajaros, originan perdidas considerables al agricultor
y al comerciante.
<FIGURE 130>

51ap141a.gif (486x486)

   La manera de evitar tales perdidas, es el control sobre las causas antes mencio
nadas, mediante un manejo eficiente de los granos, y dandoles una adecuada proteccion
durante el almacenamiento.
   La humedad, el primero de estos factores, puede controlarse de una manera
efectiva, mediante un buen secamiento del grano, antes de guardarlo en el almacen
o granero; bajando su contenido de humedad hasta un 12% o sea cuando este bien
<FIGURE 131>

51ap141b.gif (540x540)

    Each year, during the period between the time of harvest
and the time when the grain reaches the consumer, there are
considerable losses for the farmer and merchant.  These losses
are due to excess grain moisture, the attack of rodents, molds,
insects and birds.
These factors affect the good storage of grain
   The best way to prevent such losses is to control the
causes by proper handling and adequate protection of the grain
during storage.
   Dampness, the first of these causes of grain loss, can be
controlled effectively by good drying before storage. The safe
moisture content for corn is 12% or lower.
                             DRYING THE PRODUCT TO 12% OR LOWER
   Practicamente, podemos calcular, si la humedad en el grano esta buena para
conservarlo, cuando al morderlo, este se quiebra, sin presentar elasticidad y que
no este lechoso.
   Tambien podemos saber que el grano no esta aun bueno para almacenarse, cuando
al introducir la mano entre estos granos, sentimos el calor proveniente de ellos,
que por exceso de humedad se encuentra en plena actividad respiratoria; en cambio,
se sentira fresco el grano cuando debido al secamiento, haya disminuido dicha actividad;
entonces los granos estaran reposando y podran ser almacenados, sin mucho
riesgo de que se desarrollen hongos, y sin peligro de que se pudran.                  
<FIGURE 132>

51ap143.gif (393x486)

   La humedad y el calor excesivos, son ambientes propicios para que se desarrollen
hongos que ocasionaran dano al producto que se almacena.
   El dano por roedores puede evitarse en gran parte proporcionando al local de
almacenamiento una adecuada proteccion, contra el acceso de las ratas.   Tambien
manteniendo los alrededores del granero limpio de malezas y desperdicios, ya que
estos roedores prefieren no movilizarse por sitios despejados.
   Es muy efectivo para su control el uso de raticidas en forma de cebos, de los
que se venden en el comercio, tales como Racumin, Zelio, etc.
   No se deben dejar estos cebos al alcance de los ninos ni de los animales domesticos,
porque son productos muy venenosos.
   In practice, we can check the moisture content in the grain
which is safe for good storage by biting it.  Dry grain is hard,
so it will break with a sharp crack, rather than crushing easily
like wet grain.
   We can also find out if grain is in good condition for storage
by touching it.  If we feel heat rising from the grain, it
is too wet.   If the grain is excessively wet, it will respire,
producing heat and moisture.  On the other hand, dry grain will
feel cool.   If grain is giving off heat, it should be dried
immediately to assure storage without risk of mold development
and rotting.
       TOO MUCH                                      LITTLE MOISTURE
        HEAT                             LITTLE HEAT
       TOO MUCH                                      12% MOISTURE
   Moisture and excessive heat are favorable conditions for
the growth of molds which will damage the grain.
   Damage by rodents can be avoided to a large extent by
protecting the storage area against the invasion of rats.  Also,
the surrounding areas of the granary should be kept clean of
weeks and garbage as rodents prefer not to move through open,
clear areas.   The use of pesticides such as Racumin, Zelio,
etc., in the form of bait, is effective for control of rodents.
   These pesticides should not be Left within the reach of
children or pets because they are extremely poisonous products
and can cause serious illness or death.  Rat poisons should
always be used very carefully, following recommended instructions.
<FIGURE 133>

51ap145a.gif (486x486)

   El dano por insectos, es el que generalmente causa mayores perdidas en los
productos que se almacenan.  Su control se debe ejercer desde el momento en que
esta comenzando a florecer en el campo el maiz que se piensa cosechar y almacenar.
En este tiempo en que ya esta espigando el maiz, los insectos pueden estar en
alguna troja infestada, cercana al plantio de maiz; vuelan hacia el campo en busca
de nuevo alimento y comienzan a penetrar la mazorca por las aberturas de la tuza:
resultandoles mas facil la penetracion, cuando esta tuza ofrece escasa protection
al grano.
   Es por esto que algunas variedades mejoradas, se pican mas facilmente que las
variedades criollas, pues estas, generalmente poseen buena cobertura.
<FIGURE 134>

51ap145b.gif (432x534)

                      PLACEMENT OF BAIT FOR MICE/RATS
            CANS                     BAMBOO              BOXES
                      IN PLACES TRAVELED BY RATS OUT
   Generally, the greatest losses in stored products are
caused by insect damage.  Insect control should be exercised
from the moment the corn is beginning to mature in the field
through the time when the corn is harvested and stored.  Insects
may be in an infested barn, near the grain field, flying through
the field in search of new food, or already beginning to
penetrate the ear of corn through openings in the corn husk.
The only natural protection of the ear of corn is the husk, which
can be penetrated by insects.
   Some of the newly developed varieties of corn have husks
which are more easily penetrated than traditional domestic
varieties.   Extra precautions against insect invasion need to be
taken with these newer varieties.
                                              THE CYCLE OF INFESTATION
                                              BEGINS IN THE
                   PREVENT INSECTS FROM
                   FLYING TO THE FIELD
                   AND CLEAN THE BARN
            INSECT                                      MATURE CORN
                                INFESTED CORN
<FIGURE 135>

51ap147.gif (600x600)

                                          6 OUNCES (175 c.c.)
                                          MALATHION LIQUID 57%
                                             1 GALLON WATER
     In order to prevent infestation in the field, the granary
should be cleaned of all the remains of the previous harvest,
which may be infested, and these remains burned or destroyed.
Next make an application of Malathion liquid of 57% by diluting
17 1/2 spoons (16 oz.) of this insecticide in a gallon of water.
Using a sprayer, completely cover the ceiling, walls, and
floor surfaces of the granary.  With a gallon of this mixture,
a surface of 111 square yards can be covered.
                               APPLY MALATHION LIQUID ON THE
                               WALLS, CEILING AND FLOOR OF THE
                                               MATURING CORN
                               BURN THE REMAINS
   Al llevar el maiz cosechado hacia la troja o granero, para almacenarlo, se deben
seleccionar las mazorcas sanas, evitando guardar mazorcas picadas que infestarian
a las otras mazorcas.
<FIGURE 136>

51ap149a.gif (353x437)

   No se debe dejar el maiz ya maduro doblado o sin doblar en el campo, por mucho
tiempo, porque queda expuesto a la infestacion de insectos y al ataque de ratas
y pajaros, durante un periodo mas prolongado.  Se debe proceder a la cosecha, tan
pronto como lo permitan las condiciones del ambiente y el contenido de humedad del
   Para proteger al maiz que se va almacenar en trojas, se recomienda aplicar el
insecticida Malathion en polvo al 2%.  Este se debe aplicar por capas, es decir colocando
primero, sobre el piso donde estara la troja, una ligera capa de insecticida,
despues se coloca la primera capa de mazorcas, luego otra capa de insecticida,
y asi sucesivamente hasta dejar la troja llena a la altura deseada.   Las dosis
que se recomiendan para el uso de este insecticida estan de acuerdo al tamano de
las mazorcas.   Asi, tenemos que para los hibridos y variedades mejoradas, como
el tamano de la mazorca es un poco grande, hay que aplicar una onza de Malathion
2% en polvo (Triangulo Verde) por cada 100 mazorcas con tuza.   Para las variedades
criollas, como las mazorcas son mas pequenas, se debe aplicar una onza del
insecticida por cada 150 mazorcas con tuza.
<FIGURE 137>

51ap149b.gif (393x486)

    When the harvested corn is brought to the barn or
granary for storage, the best ears of corn should be selected.,
avoiding the storage of ears which are already infested with
insects, as these insects can easily infest other ears of corn.
     The ripened corn, whether piled on the ground or still
on the stalk., should not be left in the field too long because
over a prolonged period of time it is exposed to the
attack of rodents and birds.  The harvest should be carried
out as soon as the climatic conditions and moisture content
of the grain permit.
      To protect the corn to be stored in barns, it is
recommended that 2% Malathion insecticide in powder be applied.
      This should be applied in layers.   First, dust a thin
layer of insecticide on the floor where the grain will be
stored.   Next, after the first ears of corn are placed, dust
another layer of insecticide and so-on until the barn is filled
to the desired level.  The doses recommended for the use of this
insecticide are in accordance with the size of the ears of corn.
Thus, we have to apply one ounce of 2%  Malathion in powder
(green triangle) for every 100 ears of hybrid and newly developed
varieties.   As the ears of the native varieties are smaller, one
ounce of insecticide for every 150 ears should be applied.
   Este polvo debe ser espolvoreado sobre la superficie de todas las mazorcas, de
modo que las proteja totalmente.  Se puede lograr una aplicacion uniforme, utilizan
do una media de tela de Nylon o cualquier bolsa de tela rala, que permita al polvo
filtrarse facilmente hasta las mazorcas.
<FIGURE 138>

51ap151a.gif (437x540)

   Se debe aplicar exactamente la cantidad de insecticida que se recomienda y seguir
los metodos indicados, para evitar malos efectos del polvo por una defectuosa
<FIGURE 139>

51ap151b.gif (486x486)

                                           POWDER (GREEN TRIANGLE)
                                           FOR EVERY 100 EARS
NATIVE CORN                                 HYBRID CORN
      This powder should be sprinkled on the surface of all
of the ears of corn in a way that totally protects them.  A
uniform application may be obtained by using a nylon sock or
any sack or bag with a loose weave which permits the powder to
be filtered easily through to the ears of corn.
Apply 2% Malathion in
powder uniformly over
each layer
      In order to avoid problems caused by the improper
application of insecticide, the exact recommended quantity
should be used and the indicated methods followed.
                        Appendix B
This Appendix contains excerpts from an article which appeared in
Tropical Stored Products Information in 1971.  It is included here
to give you some idea as to the types and number of moisture meters
which are available.  A Table included at the end of this article
also lists the names and addresses of the manufacturers and/or suppliers
of the meters so that you can write for further information.
The following material is taken from Tropical Stored Products Information,
Tropical Products Institute, 1971 VOL. 21
                                   T N Okwelogu
                       Tropical Stored Products Centre
                    (Tropical Products Institute), Slough
Sources of Information
The three principal sources of information available to the prospective user are (1) newspapers, magazines
and journals, (2) manufacturers' brochures, and (3) organizations in a position to give unbiased
information about moisture meters.
Some newspapers, magazines and journals, which occasionally contain information about meters, include
the Financial Times, Electronic Age, and Power Farming.  Whilst manufacturers are always helpful in
supplying plenty of information about their own range of meters, information about a much wider range of
meters will be more likely to be obtained from organizations having unbiased interest in these instruments.
Examples of such organizations are (1) Tropical Stored Products Centre, (Tropical Products Institute),
Slough, England, (2) Grain Storage Department, Pest Infestation Control Laboratory, Ministry of Agriculture,
Fisheries and Food, Slough, England, (3) National Institute Of Agricultural Engineering, Wrest Park,
Silsoe, Beds, England, (4) Grains Division, Agricultural Marketing Service, United States Department of
Agriculture, Agricultural Research Centre, Beltsville, Maryland 20705, USA.   Articles on moisture meters
sometimes appear in the publications of these and other similar organizations.
Tables I and II give details of some available moisture meters, particularly how they can be obtained and
the commodities with which they may be used.  These details are based upon information provided by the
manufacturers of the meters.
With every piece of information, it is important to ask the question:   is this information sufficient for a
decisive opinion to be formed about the meter?  Where the answer is `no', further enquiries should be made.
Factors to Consider in Making a Choice
It can be seen from Tables I and II that for any specific purpose, several meters can be found, making the
problem of choice a real one, indeed.  A satisfactory selection is likely to be achieved when adequate
thought has been given to the following factors:
      1. Meter types and their implications.
      2. Characteristics of the commodity.
      3. Requirements of the work for which a meter is sought.
      4. Business considerations.
Principles and implications of Meter Types
Most manufacturers indicate the principles upon which the action of their meters is based.   An appreciation
of the implications of such principles will, no doubt, be of considerable value in deciding which of
several meters will be the most suitable.  The meters commonly used with durable agricultural products
fall into five groups, according to the principles of their action:
      1.  Those involving chemical interaction between calcium carbide and the product water, with the
          evolution of acetylene gas, the pressure of which is subsequently measured.
      2.  Those involving heat-drying of the product, the attendant loss being ascribed to evaporated
          produce water.
      3.  Those involving the measurement of electrical conductivity (or resistance) of the product, since
          the value of this property is relatable to the moisture content, within a suitable range of
          moisture contents.
      4.  Those involving the measurement of the dielectric constant of the product (or capacitance of
          the electrical system of which the product is a component), since the value of this property
          changes with the moisture content, within a suitable range of moisture contents.
      5.  Those involving the measurement of that atmospheric relative humidity which is in equilibrium
          with the product moisture, since, under equilibrium conditions, there is a definite relationship
          between the moisture content of a product and the ambient relative humidity
              Heat-drying methods require a suitable source of power-supply or fuel, which may not be
available.   Methods based on the evolution of acetylene gas require regular, supplies of fresh calcium
carbide, which is not a safe commodity to handle by post, because of the risk of explosion.   Meters measuring
the inter-granular relative humidity  require, firstly, a knowledge of the relationship between the produce
moisture content and the relative humidity of the inter-granular air:   secondly, a periodic check on
their calibrations; and thirdly, in some cases, large quantities of produce which must have remained undisturbed
for sometime prior to testing.
The electrical meters are faster, and in the main, less demanding on calibration checks, but require
skilled servicing.  Also, they give less reliable readings outside the middle region of the range of moisture
contents for which they are calibrated.  The accuracy of the probe-type electrical meters is affected
by variations in the pressure exerted by the produce on the electrodes, while the consistency of the readings
of those meters which measure the dielectric constant is affected by inconsistent packing of the
sample in the test chamber.
Attention has been focused above on the less favourable features of the meter groups mainly because they
are more likely to be overlooked.  Information on the merits of any meter will not normally be difficult to
obtain, and Tables I and II show the relative merits of the meters discussed in the present article.
Characteristics of the Commodity
The commodity to be tested imposes a number of limitations, and these must be taken into account when
considering the use of any meter.  Perhaps the best way to do this is to answer questions such as the
First, is the chemical nature or any normal pre-treatment of the produce likely to interfere with the use of
the meter?   For instance, meters measuring electrical conductivity may not be suitable for produce, like
salt-fish, which will become highly conductive when damp.  Again, for commodities like dried egg or milk,
a heat-drying meter may not be suitable.
Second, is the moisture content to be measured outside the range for which the meter is calibrated?  For
example, very few electrical meters are known to be suitable for a product like made-tea whose moisture
content is normally required to be below 5 per cent, that is outside the range of moisture contents for
which most electrical meters are calibrated.
Third, is the milling property of the produce incompatible with the effective use of the meter?  For
example, commodities like macadamia nuts, palm kernels and copra are not easily ground, while others
like cashew nuts (not the kernels) are simply not amenable to grinding.
Fourth, are the unit size and shape of the produce likely to affect the efficient use of the meter?  The
construction of the meter may be such that it cannot be pushed into floury or powdery produce without
hampering the measurement of moisture.  Again, larger products like cocoa beans, unshelled groundnuts,
cashew nuts and pieces of illipe nuts (Shorea spp.) will present packing problems with some meters.
If the answer to each of the above questions is an unqualified `No', then the meter may be considered
suitable for the product.  But a `Yes' answer can make all the difference between a meter being chosen
or rejected.   In such a case, steps should be taken to see what, if anything, has been done to solve the
problem, either by the manufacturer or by someone else.
Nature of the Situation Needing a Moisture Meter
In an article of this kind, it is not easy, even if it is possible, to cover all the situations where the use
of a moisture meter may be desired.  However, such situations are likely to fall into one or the other of
the following categories:
       1.  Knowing whether grain is at the right stage for harvesting.
       2.  The processing, (eg drying or milling), of foodstuffs.
       3.  Bulking or packaging produce for storage.
       4.  Commercial transaction, where moisture content is part of the basis for payments.
       5.  Produce Inspection Service.
All the above situations require moisture meters which are not fragile, which are consistently accurate
within limits acceptable for the particular purpose, and whose performance is little affected by the operating
conditions of space, temperature, pressure, light, dust or wind.  They also require, to a greater or
lesser extent, meters that are simple to operate, portable and capable of taking remote measurements, as
with probe-electrodes, or stem hygrometers.
Business Considerations
The purpose for which the use of a meter is usually contemplated is two-fold:   to increase or improve
productivity, (that is, the flow of goods and services), and to ensure economical operations.
Productivity can be improved by employing a meter which can give results rapidly; a meter for which
spares and facilities for servicing and/or calibration are easily available; a meter which does not depend
upon sources of operating power that run out, break down, or become short in supply (eg battery, mains
supplies, gas, paraffin and other fuel).
Economy of operation implies keeping down to the minimum both capital and operating costs, and/or
increasing the return to unit cost.  Additionally, the wider the range of commodities that a meter can test,
the more economical will be its use.  Likewise, the less destructive a test is, the less will be the
incidental loss to production, caused by the use of a meter.  Although this kind of loss may appear small,
it must be realised that its magnitude will depend on how much produce is damaged at each test, and how
many times such tests are carried out on a given product.
It should be clear from these discussions that very few meters, if any, can win the top position in every
conceivable area of consideration, and that there is no magic formula for choosing a meter.   But where a
choice has to be made, the final responsibility for it must be that of the buyer.
He must have a knowledge of the commodity to be tested and the accuracy required of a determination of
its moisture content the availability of the meter, and the cost of operating it; the conditions under which
the meter will be operated:  the ease of obtaining spares and facilities for servicing or calibrating the
meter:   the type of power supply required and available.  And when a provisional choice has been made, it
is often advisable to obtain the meter on loan for trial before buying.
ANON. 1953.   The Quicktest grain moisture tester.   [/I]Report nat. Inst. agric. Engng, No. 83 (Nov.), 5 pp.
ANON. 1966.   Farm grain drying and storage.   [/I]Min. Agric. Fisheries and Food, Bull., No. 149, 123-129.
BANNER, E H W. 1958.  Electronic measuring instruments.  London:   Chapman and Hall, 2nd edn, revised
    xi, 496 pp.
LEFKOVITCH, L P and PIXTON, S W. 1967.  Calibrating moisture meters.  J. stored. Prod. Res., 3 (2),
MACKAY, P J. 1967.  The measurement of moisture content.  Trop. stored Prod. Inf., (14), 21-29.
PANDE, A and PANDE, C S. 1962.  Physical methods of moisture measurement.  Part 1:   Conductivity.
    Instrum. Pract., 16(7), 896-903.
PANDE, A and PANDE, C S. 1962.  Physical methods of moisture measurement.  Part 2:   Dielectric, sonic,
    ultrasonic, microwave and electrolytic methods.  Instrum. Pract., 16(8), 988-995.
PIXTON, S W. 1967.  Moisture content - its significance and measurement in stored products.   J. stored
    Prod. Res., 3(1), 35-47.
STEVENS, G N. 1968.  The measurement of grain moisture content by rapid methods.  Tech. Note Home-Grown
    Grown Cereals Auth. No. 5, 3 pp.
WARNER, M G R and HARRIES, G O. 1956.  An investigation into the performance of five typical rapid
    methods of measuring the moisture content of grain.  Report nat. Inst. agric. Engng, No. 46, (Mar.),
    43 pp.
ZELENY, L and HUNT, W H. 1962.  Moisture measurement in grain.  For presentation at the 1962 Winter
    Meeting of the Amer. Soc. Agric. Engineers, Chicago, Illinois, Dec. 11-14.  Paper No. 62-926, 32 pp.
    (Details from the authors:   Standardisation and Testing Branch, Grain Division, Agric. Marketing
    Service, USDA, Agric. Research Centre, Beltsville, Maryland).
                                   Table 1 Details of some available proprietary moisture meters(1)
Meters under principles    Power supply:        Test speed:           Accuracy       Price rating:                    Manufacturer/Supplier
       of action           B Battery             + Under 1 min     (Within % MC)      * Under 50 [pounds]
                          G Self-generating    ++ 1-5 min                           ** 50 [pounds] - 100 [pounds]              
                          M Mains              +++ over 5 min                       *** Over 100 [pounds]
                          N None required
       CHEMICAL (C)
C.1     Speedy                      N                  +++                  0.5              *                           Thomas Ashworth & Co Ltd
                                                                                                                    Sycamore Avenue
                                                                                                                    Burnley, Lancs, England
       DRYING (D)
D.1     X17 Agat                    M                  +++                  0.3              *                          A.B.G.L. Jacoby
                                                                                                                    Box 23014Y, Stockholm 23
D.2     Cenco Moisture              M                 ++                  0.2               *                           Cenco Instrumenten Mij, n.v.
       Balance                                                                                                       Konijnenberg 40, Post Box 336
                                                                                                                    Breda, Holland
D.3     Dynatronic IR               M                 ++                  0.2             ***                           Lab-Line Instruments
       Moisture Analyzer                                                                                             International Lab-Line Plaza
       Mark II                                                                                                       15th & Bloomingdale Aves,
                                                                                                                    Melrose Park, Illinois, USA
D.4     ts Crop Tester              M                +++                   1.0              *                          Tower Silos Ltd
                                                                                                                    2 Block Street, Bath
                                                                                                                    Somerset, England
D.5     Vacuum Moisture             M                 ++                  0.1             ***                           Townson & Mercer Ltd
       Tester                                                                                                        Croydon CR9, 4EG, England
Ec.1    KPM Aqua Boy                B                  +                  0.2              **                          K.P. Mundinger GmbH
                                                                                                                    D-7253 Renningen, W. Germany
Ec.2    Universal Moisture          G                  ++                  0.2            ***
       Tester                                                                                                        Burrows Equipment Co
                                                                                                                    1316 Sherman Avenue
Ec.3    Safe Crop Moisture         B,M                 ++                  0.5             **                           Evanston, Illinois, 60204 USA
Footnotes are explained on p. 28.
                                               Table I (contd)
Meters under principles    Power supply:        Test speed:         Accuracy       Price rating:                    Manufacturer  Supplier
      of action            B Battery            + Under 1 min    (Within % MC)      * Under 50 [pounds]
                          G Self-generating   ++ 1-5 min                           ** 50 [pounds] - 100 [pounds]
                          M Mains             +++ over 5 min                       *** Over 100 [pounds]
                          N None required
          ELECTRICAL CONDUCTIVITY (Ec) (contd)
Ec.4       Agil Moisture Meter      B                   +             1.0 - 2.0             *                         Agil Ltd, Nicholson House
                                                                                                                  Nicholson's Walk
                                                                                                                  Maidenhead, Berks, England
Ec.5       Hart Moisture Meter     B,M                  +               0.2               ***                         Hart Moisture Meters, Inc
          K101. K103                                                                                               400 Bayview Ave, Amityville
                                                                                                                  N.Y. 11701, USA
Ec.6      `Hydraprobe'              B                  +               2.0                  *                         Coe's (Derby) Ltd
         Copra Moisture                                                                                            Thirsk Place, Ascot Drive
         Meter                                                                                                     Derby, D'E2 8JL, England
Ec.7      Marconi Moisture         B,M                  +               0.5                **                         Marconi Instruments Ltd
         Meter TF933B                                                                                              Longacre, St Albans
                                                                                                                  Herts, England
Ec.8      Protimeter                B                 ++              0.5                  **                         Protimeter Ltd
         Grainmaster                                                                                               Field House Lane
                                                                                                                  Marlow, Bucks, England
Ec.9      ScotMec-Oxley             G                  +              1.0                  **                         Scottish Mechanical Light
                                                                                                                   Industries Ltd
                                                                                                                  42-44 Waggon Road, Ayr
Ec.10     Siemens Moisture         B,M                ++              0.5                 ***                         Siemens (UK) Ltd
         Meter                                                                                                     Grt West House, Grt West Rd
                                                                                                                  Brentford, Middx, England
Ed.1      Cera Tester               B                  +              0.3                  **                         A/S N. Foss Electric
                                                                                                                  39 Roskildevej, 3400
                                                                                                                  Hillerod, Denmark
                                                    Table I (contd)
Meters under principles    Power supply:             Test speed:        Accuracy       Price rating:                 Manufacturer/Supplier
     of action             B Battery                  + Under 1 min   (Within % MC)     * Under 50 [pounds]
                          G Self-generating         ++ 1 -5 min                        ** 50 [pounds] - 100 [pounds]
                          M Mains                  +++ over 5 min                     *** Over 100 [pounds]
                          N None required
        DIELECTRIC CONSTANT (Ed) (contd)
Ed.2     Kappa-Janes            B,M                        ++                 0.5              ***                    Kappa Janes Electronics
        Moisture Meter                                                                                             27 Stewart Avenue
                                                                                                                  Shepperton, Middx, England
Ed.3     Burrows Moisture        M                       +++                 0.3              ***                    Burrows Equipment Co
        Recorder                                                                                                   1316 Sherman Ave, Evanston
                                                                                                                  Illinois 60204, USA
Ed.4     Lippke Moisture         M                         +                0.5               ***                     Paul Lippke K.G. 545 Neuwied
        Meter FK-R-6                                                                                               PO Box 1760, Germany
Ed.5     Wile                    B                         ++                 1.0                *                    OY Fima Ltd, Helsinki 70
Ed.6     Super-Matic Foss        M                        ++                0.3               ***                     A/S N. Foss Electric
                                                                                                                  39 Roskildevej, 3400
                                                                                                                  Hillerod, Denmark
Ed.7     Transhygrolair          B                         -                1.0                 *                     Les Applications
                                                                                                                  Industrielles de la Radio
                                                                                                                  236 Chemin des Vitarelles
                                                                                                                  Tournefeuille (31) France
Ed.8     Steinlite Meters       B,M                       ++                0.3               ***                     Seedburo Equipment Co
                                                                                                                  618 West Jackson Boulevard
                                                                                                                  Chicago, Illinois 60606 USA
Ed.9     Dole 300 Moisture      B,M                         +                  -                **                    Eaton Yale & Towne Inc
        Tester                                                                                                     Dole Division, 191 E North
                                                                                                                  Avenue, Carol Stream
                                                                                                                  Illinois 60187, USA
Ed.10    Cae Moisture            B                          +                 0.3               **                    Canadian Aviation Electronics
        Meter Model 919                                                                                            Ltd, Winnipeg 4, Canada
                                                Table I (contd)
Meters under principles    Power supply:          Test speed:       Accuracy      Price rating:                     Manufacturer/Supplier
      of action            B Battery             + Under 1 min   (Within % MC)      * Under 50 [pounds]
                          G Self-generating    ++ 1-5 min                         ** 50 [pounds] - 100 [pounds]
                          M Mains              +++ over 5 min,                    *** Over 100 [pounds]
                          N None required
Ed.11   G-c-Wyndham              B                     +            0.5 - 1.0              *                         E J Chapman & Co Ltd
       Moisture Meter                                                                                              Martley, Worcester, England
Ed.12   C.D.C. Automatic         M                     +               0.3               ***                          Compagne des Compteurs (GB)
       Moisture Meters                                                                                             Ltd, Terminal House
       Hyb 24, Hyb 25           B                      +                0.5               ***                          Grosvenor Gdns, London SW1
       Hyb 42, Hyb 43                                                                                              England
H.1     Dip-Shaft                N                   +++               1.0                 *                          Abrax Inc, 179/15H Jamaica
       Humidity Indicator                                                                                          Ave, Jamaica,
                                                                                                                  New York 11432, USA
H.2     Quicktest                N                   +++               1.0                 *                           Opancol Ltd
       Models 1 and 2                                                                                              10/11 Gamage Building
                                                                                                                  Holborn Circus, London EC1
       (1)  All the information given in this table has come from the manufacturers
        -   Data not available
        NB The exclusion of an instrument from this table does not necessarily
          imply the author's disapproval of its use with agricultural produce.
                          Appendix C
                        WORKING PAPER ON THE
The following working paper was originally presented at a regional
grain storage seminar held in Cotonou, Benin, West Africa, in 1974.
The seminar was sponsored by the International Secretariat of Voluntary
Services, the UN Food and Agriculture Organization, and the
U.S. Agency for International Development.
The seminar's purpose was to encourage the initiation of farmer-oriented
storage extension programs through the sharing of practical information
and field experiences.  It was attended by over 100 participants from
nineteen countries in Africa, Europe, and North America.  A handbook/report
was published, by the German Agency for Technical Cooperation Ltd.,
which includes all working papers, discussions (summarized), and construction
plans for various silo and dryer models reviewed during the
seminar.   Several of the modified plans presented in this manual are
included in the seminar report.  It is available from the seminar secretary,
Mr. David Dichter.  His address is:   David Dichter and Associates,
Development Assistance Programmes, 9 rue de Vermont, 1202 Geneva, Switzerland.
              DECEMBER 13-23, 1974
                COTONOU, DAHOMEY
              WORKING PAPER No. 1
                                    Carl Linblad
                                    Mark Newman
                                    Roger Vinita
                                         United States Peace Corps
                                         Volunteers to Dahomey (Benin)
                                    Attached to the
                                    Agriculture Service
                                    Ministry of Rural Development
                                     and Cooperative Action
       Since 1967, the Agriculture Service of Dahomey and the United
States Peace Corps have collaborated in creating, implementing and
evolving a farm-level grain storage program in southern Dahomey.   One
result of this joint program is the actual construction of over two
hundred and fifty individual storage units.  Another result is
seven years of cumulative experience in working through some of
the practical day-to-day problems of popularizing new farm-level grain
storage technology.  This shared experience by two organizations, one
a governmental agency and the other an international volunteer agency,
forms the basis for this paper.
       The authors see the primary purpose of this paper as a presentation
of some of the major considerations in the planning and
establishment of a farm-level grain storage program.  Of secondary
importance is a brief history, attached as an appendix, of the
collaboration of the Agriculture Service and the Peace Corps in
evolving the program.
       While the authors' program is limited to Dahomey and primarily
one type of storage facility; it is hoped that their practical
experience will be of benefit to others initiating similar programs,
regardless of the storage method adopted.  The paper is not an
instruction manual nor a "how-to-do-it" guide to popularizing new
techniques in grain storage.  Rather, it is a brief discussion,
with specific examples based on the author's experience of five
major areas of concern in planning a new grain storage project:
       1.  Assessment of the problem
       2.  Choice of the improved method to popularize
       3.  Financial considerations
       4.  Stimulating interest in improved storage methods
       5.  The extension and integration of the project into the
           local infrastructure.
(1) See "Construction Manual for the 4.5 Ton and 2.5 Ton Cement Silo
    and the Mud Walled Grain Dryer" by U.S. Peace Corps Volunteers,
    October 27, 1974.
Part I.   Assessment of the Problem
       The initial phase in the planning of a project to improve grain
storage technology is an analysis of the problem from the point of
view of the farmer in the particular locality to be served.  He is
the key ingredient.  Any program must be based upon realities as seen
by the farmer who will be storing his grain.
       In Dahomey, the traditional corn-growing farmer lives in a
small village and annually cultivates up to 3 hectares (7 - 1/2 acres)
by hand.   His annual yield with two growing seasons could be estimated
at 600-800 kg/hectare or a total of 1,800-2,400 kg.  This is classic
subsistence farming, probably not unlike that of most corn-growing
farmers in the developing world.
       Traditional storage methods.   Initially in the consideration,
choice and planning of an improved storage program it is advisable
to analyze local traditional methods in order to (1) understand their
shortcomings and therefore the need for improved techniques and (2)
investigate for possible simple, yet effective, improvements.  Certainly,
minor and effective changes to existing methods of storage are easier
to popularize than the introduction of complex and costly alternatives.
For example, perhaps improved sealing of traditional granaries or
a broad-based program of insecticide treatment could have significant
immediate effects.
       At any rate, the important point is to think about the traditional
methods of storage from the farmer's viewpoint.  Does he find that the
traditional methods are inefficient?  Does the rapid rate of insect
multiplication make it impossible to store grain over a long period
of time with his traditional method?  Do mold growth and rotting present
Problems?   What about rodents and birds?   How much grain does he actually
lose with his traditional methods of storage?
       Market Price Realities.   As a practical matter, farmers will not
be inclined to change their traditional storage methods unless there
will be sufficient financial returns from whatever additional labor,
time or cash inputs are required by the improved storage techniques.
Therefore, the economics of the improved techniques as affecting subsistence
farmers must be carefully studied.
       Local market price information is needed.   What are the prices
of grain at harvest time and at the yearly high?  Also, does the farmer
have large financial demands at harvest time?  What are his spending
habits?   Does he normally have to sell his grain before prices have
started to reach their seasonal high?  How much fluctuation is there in
the price on the local market?  Are there other more lucrative markets
he can reach easily?  Is transportation of his crops to the market expensive
or impractical?
       There are other economic and market factors to consider.  For
example, traditionally, grain in Dahomey is sold in markets by volume
rather than by weight.  This could work against the adoption of improved
storage methods.  The improved quality of well-stored grain, for instance,
could bring few benefits if the farmer not using improved methods can mix
a large proportion of his damaged corn with good grain and thus sell it
at the same price as well-stored grain.
       Similarly, are grain prices keeping pace with inflationary price
rise in the cost of the new storage techniques?  Also, increased transportation
prices, for example, can reduce potential profits.  In short,
the economies, that is, the practical benefits of a new method, must be
thought through from the farmer's standpoint or, it may fail to be
accepted because of simple economic realities.
       Social Customs and Traditions.   Similarly, local customs and
traditions should be carefully studied from the farmers viewpoint to see
what impact they might have on the introduction of a particular storage
technique.   The use of insecticides, for example, may require careful
planning.   If farmers are used to leaving their maize unhusked during
storage, will they resist?  Will insecticide-treated grain have a changed
taste or odor?   Is treated grain acceptable by the farmer for his own
consumption?   Is it acceptable for sale locally?   Have there been any
bad experiences in the locality as a result of the misuse of insecticides?
       Another example of the importance of social customs is the farmer's
attitude toward centralization of storage facilities.  Does the farmer
traditionally build a granary in his field and leave the crops stored
there until needed?  Would a central storage silo cause him transportation
problems?   Will he resist co-operative storing because he doesn't want
his neighbor to know how much he has produced?  Social factors such as
these can affect the success of a new storage program.
       Having analyzed the problems from the point of view of the farmer,
the planning agency or organization must decide upon the scope of the
program it hopes to introduce and to what extent it can support the program.
       Personnel considerations.   The providing of new information and
training and support for the introduction of improved storage methods
requires considerable personnel.  Does the agency have sufficient manpower?
Will the personnel need training in the new techniques?  Will voluntary
extension personnel be needed?  To whom will volunteers be responsible?
What will their role be in relation to the permanent extension personnel?
How will coordination be arranged?  Is the organizing agency willing to
assign permanent personnel to assure the success of the program?   Staffing
and training, therefore, are extremely important in planning a new program.
       Material Availability.   The supply of necessary materials must be
assured as well.   To what extent is the project dependent upon vital
materials which are influenced by outside forces, ie., regional or world
shortages, inflation.  Cement, insecticides, tin sheeting, re-rod, sand,
water, screening, wood ---- are they readily available?  Who will be
responsible for assuring the supply of needed materials?  How reliable
is that person or agency?  How reliable is the supply?  Lack of critical
items when needed will undermine the farmer's confidence in the program.
       Transportation.   Are local transportation facilities available and
adequate for the needs of the program?  If they are not, provisions for
vehicle support must be made.  In such a case, decisions must be made as
to the use of the vehicles before precedents are set.  If farmers are
dependent on a project to transport their harvests, this may prevent the
development of local transport and cause difficulties when the project
can no longer continue such support.
       Commercialization.   Marketing success of grains stored using
improved methods will influence the rapidity with which those methods
are accepted.   For example, if local market prices do not fluctuate
as greatly as those in urban centers, the sponsoring agency may want
to consider the planning and support of organized transportation for
commercialization.   The program should consider the available means of
commercialization and look for improvements to enhance the value of the
improved storage techniques.  For example, the sponsoring agency may want
to reward farmers for the improved quality of their grain by introducing
some system of quality grading or sale by weight to help popularize their
       The above brief summary includes some of the major factors an
agency must evaluate in deciding at what level it is willing to and
capable of participating in a program for new grain storage techniques.
       Having thus considered the problem, one is better prepared to choose
the particular means of improving storage which is best suited for the new
Part II.   Choice of the Improved Method to Popularize
       The choice of an improved storage technique for popularization
should result from an analysis of the existing problems.  Clearly, the
economic factor will weigh very heavily.  In dealing with subsistence-level
farmers with very limited cash resources, the total cost of construction,
repair and utilization of a new technique must be measured
carefully against the effectiveness and practical benefit to the farmer.
This type of calculation generally requires time for both study and testing
of the new method, two factors which are important to the process of choosing
a storage technique.
       Scientific testing.   The importance of scientific testing cannot be
over-estimated.   Such analysis, before introducing the new storage technique
to the farmer, can avoid many problems.
       Scientific testing lends authenticity and permits the sponsoring
agency to defend confidently such factors as reliability and efficiency.
For example, the Institute of Research for Tropical Agriculture (IRAT),
in Dahomey, has greatly advanced storage techniques in that country by
its testing of many storage methods, among them; local granaries with
and without insecticides, cribs, artificial dryers, cement stave and metal
silos.   The results of these experiments have produced information important
to the planning, choice and policy of grain storage programs in Dahomey.
       Testing, therefore, is an important step in choosing a particular
method of improved grain storage.
       Field Experience.   Less formal, but equally revealing, is field
experimentation.   For example, field trials can help to verify the
adaptability of local materials as substitutes for more obvious and costly
imported materials.
       Field tests uncover hidden problems and unanticipated social
impediments.   They can indicate the level of farmer interest in the proposed
new technique.
       An example of the value of field tests in Dahomey was demonstrated
when they revealed that storage in butyl bags was impractical because common
over-filling caused bursting, and rats or sharp objects easily pierced
the bag destroying its air tightness.  In effect, the field testing of
a new technique provides a kind of market sampling of the locality before
larger-scale popularization.
The use of permanent extension agents or Volunteers in performing field
tests can be effective.  In Dahomey, for example, Peace Corps Volunteers
performed useful field experimentation in the early years that resulted
in much practical information essential to developing the grain storage
program here.
       Such field experiments must be cearly described as such to farmers
to avoid false impressions and to permit adjustments of the program.   Thus
protected, one can obtain valuable information pertaining to such additional
questions as (1) how much training time and supervision is necessary to
assure proper construction and/or proper use?  (2) can the farmer maintain
the technique himself?  (3) are special tools required?  (4) will the
existing agriculture extension system support the new technique?
       The final choice of a particular storage method to popularize will
be a balance of many of the factors previously discussed in the context
of local conditions.   To help the reader assess the various grain storage
methods presented during the seminar, a "table of consideration" is attached
to aid in one's analysis.  Participants can fill in any information which
they feel is pertinent and valuable to their specific purposes.
Part III.   Methods of Financing the Introduction of New Storage Techniques
       The organization of the financial aspects of a new program of improved
grain storage techniques is essential to the smooth start of the program.
There are several types of financing available from which to choose, among
which are included:
       1.  Direct cash investment by participating farmer
       2.  Credit financing
       3.  Price supports
       4.  Grants
1.   Direct cash investment by participating farmer
    Cash payment for any improved storage technique is the simplest
and most direct method of financing.  It requires a minimum of administrative,
financial and coordinating burdens for the sponsoring agency.   Furthermore,
cash programs using the personal financial resources of the farmer
can be the method of financing which gives the widest and fastest possible
popularization of a program, providing that they are relatively inexpensive
and accessible to small farmers.
       In countries with an average annual her capita income of less than
$100, such as Dahomey, many methods of storage which are relatively low-cost
will still be beyond the means of the average small farmer.  In this
case, high cash requirements can severely limit the scope of a program
and the speed of its acceptance.
       If the cost of the new technique is too high, the benefits derived
from the improvements may be concentrated in the hands of farmers at the
highest income level or even with merchants and civil servants who are
quick to see the monetary advantages of improved storage methods.
       Thus, other methods of financing will have to be considered if the
average farmer is to participate in improved storage programs.  Later,
as a result of his use of improved methods, his increased income may permit
him to assume more financial responsibility for additional improvements.
2.   Credit Financing
    Credit financing can increase the potential availability of improved
storage methods to the low-income farmer.
A.   Selection of credit recipients is an important consideration.  If
the project uses financial criteria similar to those used for bank loans,
most small farmers will not have sufficient resources or collateral to
merit credit.   In order to make credit available to those who need it
most, without risking a low rate of repayment, it may be necessary to allow
repayment of loans in kind or make provisions for a commercialization
program for the grain stored.
To participate in a credit program, a farmer should be asked to show his
degree of interest in the project, beforehand.  This can be judged through
the requirement of a cash advance or the supplying of specific materials
or labor.
B.   The System of repayment of the credit loan should be well-planned
before the program begins.  Provisions should be made for the eventuality
that a certain proportion of the loans will not be repaid sometimes due
to circumstances beyond his control, such as crop failure.  The terms and
requirements of the credit program must be clearly explained to all farmer
participants and to all extension personnel to assure that all parties
concerned understand the responsibilities being assumed.
3.   Price Supports
    Another way of financing a program of improved grain storage
techniques is by price support contributions by the sponsoring agency.
This is a form of gift but it is for the purpose of underwriting the
program.   For example, it might involve granting a portion of the cash
value of construction materials or transportation expenses, the remainder
being paid for by the interested farmer or cooperative.
       Price supports can provide a valuable alternative to cash and
credit financing, especially when there are rapid increases in the prices
of building materials or insecticides without equivalent increases in
the prices that farmers receive for their produce.  Price supports used
in conjunction with a cash program can serve to avoid the repayment problems
inherent in credit, thus decreasing the administrative burdens of the
       Un-repayed credit becomes a gift.   If a high percentage of reimbursement
cannot be assured by a credit program, it might be better to distribute
the available financial resources through the use of price supports.   This
would make it possible to extend the benefits of the program to more people.
       A price support program, while limited by the resources available,
has many of the advantages of a cash program.  The project personnel has a
smaller and less complicated administrative work-load than a credit program.
Another advantage is that the interest of the farmer is assured by his cash
4.   Grants
       Grants provide a means of having programs quickly accepted by
farmers; their scope is limited only by the financial capabilities of the
granting agency.  However, grants can present problems to the long-term
development of a program.  Once the project funds have been exhausted for
grant financing, it may be difficult to convince farmers to pay their own
money for what others have been given free.  In this case, there may be
a lag in popularization while farmers wait to assure themselves that no
further gifts will be forthcoming.
       There is another problem that may result from the donation of a
grant:   Since the investment by the farmer is minimal, his interest in the
upkeep and proper use of the items received may also be minimal.
       If grants for the total cost of the storage method are to be given
to farmer participants, better results may be assured by careful selection
of recipients, thorough explanation of the practical advantages and use of
the storage method, followed by continued supervision in its proper use.
Part IV.   Stimulating Interest in Improved Storage Methods
       There are many methods of popularizing a new storage technique or
of stimulating interest in it.  The manner in which it is done can directly
affect the number of farmers who will choose to try the new technique.
       It is best that the program be completely planned before commencing
active popularization at the farmer level, in order to avoid confusion
or delays.   For example, project field agents should be trained and fully
informed about the program before they begin discussing it with farmers.
The storage method should have been tested.  The financial arrangements
should be settled and agreed upon.  Transportation problems should be
resolved.   Provisions should be made for the rapid acceptance and expansion
of the program.   Once all these matters are prepared, than the popularization
can begin.
       Demonstration Methods
       Demonstration of improved storage methods can be very effective in
convincing farmers to adopt the new method for themselves.  Demonstration
models should be highly visible and built to attract a lot of attention.
Possible locations for demonstration sites are:  near the home of an individual
farmer, at farmers' cooperatives, at agricultural youth clubs, at agricultural
expositions or on publicly owned land.
       Important considerations in attracting the farmers' attention are:
Is the location easily seen?  Is adequate, easily interpreted information
provided?   If it is built for an individual farmer, is he well-respected?
Will he use the site?  Are there local personnel available who can explain
the method?   Will the site be attractive and well-maintained?
       On Farm Demonstrations
       Because of some traditional farmers' reluctance to adopt new methods,
the initial demonstration sites may need to be built on a total gift or
price-supported basis, perhaps with a guarantee to reimburse any losses
in the event of failure.  However, when the demonstration site is installed
as a gift, recipients may have little stake in its success.   Since the
purpose of a demonstration site is to spread the knowledge of good results,
special care should be taken that such sites are well chosen to reduce problems
of mis-use or abandonment.  It is a good idea for the selection of farmers
for demonstration sites to be done with the aid of local agricultural extension
or government authorities.  Additionally, close supervision and careful
explanation of storage techniques will held to assure good results and positive
       Agricultural Expositions
       The high visibility offered by agricultural fairs presents an
excellent opportunity for display, explanation and discussion of demonstration
models.   An explanation in the local language by a farmer already
convinced of the method through personal experience and success can greatly
increase the impact of an agricultural fair demonstration.  Follow-through
is increased by handing out simple flyers which briefly explain the storage
method and give names and addresses to contact for more detailed information
and assistance.
       Demonstration Sites on Public Lands
       Sites near market places, health clinics or local agricultural
offices can be very effective demonstration locations.  Since this type
of site generally has no single owner or person responsible for its
operation, assurance should be made in its planning to provide for
continued and proper use because an unused storage unit can be a bad
advertisement.   Increased credibility and effectiveness can be provided
by assistance of local agricultural extension agents in demonstration site
operation and information dissemination and by inviting local farmers
to participate in all aspects of its use.  Whenever possible, transportation
of interested farmers to a demonstration site can increase its impact.
       Use of Radio and Newspapers
       For more widespread popularization purposes, agricultural radio
programs and newspapers can be used.  Since these methods lack the visual
impact and opportunity for questions provided by actual demonstration sites,
explanations must be clearly and convincingly focused at the level of
knowledge of the prospective users, preferably in the local language or
with simple self-explanatory diagrams and pictures.
       With all of the above methods for creating interest through
demonstration and information dissemination, emphasis should be placed
on the practical benefit of the new storage method and all popularization
efforts should be designed for high visibility and comprehension at the
level of the farmers for whom the project is aimed.
Part V.   Integration into the Local Infrastructure
       A grain storage program can have a more lasting and broader impact
if it is closely integrated with agricultural extension services, farmers'
organizations, local craftmen and the local marketing structure.  Additionally,
such integration can reduce the program's organizational and logistical
responsibilities.   For example, the management of insecticide supplies
might be turned over to merchants' or farmers' organizations.  Craftmen,
once trained in storage construction skills, can take over further training
through apprenticeship of younger craftsmen.  Agricultural agents can supervise
drying, treatment and storage.  Involvement at all levels of the agricultural,
economic and social sectors will help bring about an integration
which hopefully results in adaptation of the storage method.
       Coordination with other related projects can also extend the long-range
effect of a grain storage project.  For example, a broader more effective
base might be gained by joining forces with grain commercialization programs
or improved production projects which encourage the use of fertilizers,
improved seeds and/or animal traction.  This type of coordination can provide
complementary benefits for other sectors of activity as well.
       To achieve real and continued integration, one of the project's
conscious goals must be just that, integration.  Contact between project
coordinators through regular meetings or frequent interchange can held
to keep communication going and to facilitate cooperation.   In addition,
competent and thorough training will increase the value of the project
extension workers' contribution toward integration.  Training sessions
can be held "on site" for direct experience or, in the case of large groups,
short instruction courses can be incorporated at local training institutes
or schools.
       Given the temporary nature of third-party developmental aid, a
project relying on this type of support cannot expect to have long-term
duration if integration into existing infrastructures is not undertaken.
The sooner integration begins, the less is the risk caused by the eventual
or sudden loss of outside project support, local participation and local
                 Brief History of the Grain Storage
                 Program of the Agriculture Service
                of Dahomey and the U. S. Peace Corps
       It was in 1967 that the Agriculture Service of Dahomey under the
Ministry of Rural Development first asked for U.S. Peace Corps volunteers
to assist it in implementing a new program of grain conservation at the
farm level in southern Dahomey.  Problems with grain storage had always
been acute in Dahomey.
       The vast majority of maize produced annually in Dahomey is grown
in the southern half of the country where there is constantly high
humidity and temperatures which foster rotting as well as the multiplication
of maize-consuming insects.  The traditional method of storage in
southern Dahomey is in loosely-woven palm thatched granaries raised on
wooden stilts.   The only real protection against attack by rodents and
insects is offered by the husk on each ear of maize, resulting in 30%
average loss of the 300,000 tons approximate annual production.  The
estimated value of maize lost annually to the combined effects of insects,
rodents and rot is a minimum of 600,000,000 CFA (about $3million).
       The idea behind the original request was to introduce to individual
farmers the use of the insecticide, Phostoxin, with steel drums and butyl
sacks furnished by the Office of Agricultural Commercialization of Dahomey
(now S.O.C.A.D.) under a grant by US AID.
       Thus, the initial impetus to the project was aimed at popularizing
a new storage technique at the farm level.  It also entailed assessment of
traditional systems of storage and experimentation with a variety of potential
improved methods of storage.  One of these methods was the cement stave silo,
adapted from larger models used in the United States, and the mud-walled
Brooks dryer, developed at Ibadan, Nigeria, and adopted by the Institute of
Research of Tropical Agriculture (I.R.A.T.) at Niaouli, Dahomey.
       Since the process of artificial drying and storage in a new type
of silo was experimental, and the results could not be guaranteed, the
majority of the expenses of constructing the first units for individual
pilot farmers were paid for by the U.S. Embassy Self-Help Fund.
       Over the first few years, the Agricultural Service and the Volunteers
constantly tried modifications in the design of the silos and dryers.   During
this period of experimentation Dahomean Agricultural extension agents and
local officials offered their help and advice.  Cumulative results of field
testing did indicate to the Agricultural Service and the Peace Corps that
the Cement stave silo merited carefully controlled scientific experimentation
to determine its reliability of performance.
       By 1971, it was clear that (1) farmers in Southern Dahomey were
ready to accept new methods of storing corn, (2) the earthen dryer was
effective and had potential for popularization, and (3) there were two
types of silos -- cement stave and sheet metal (the latter developed by
I.R.A.T.) which appeared promising for farm level storage.
       At this point, it was decided by the Agricultural Service, the
Peace Corps and I.R.A.T. that controlled tests should be performed.
Accordingly, an experiment was installed at the I.R.A.T. station at Niaouli.
Twelve cement stave silos and twelve sheet metal silos were built and placed
under a large shelter.  The silos were filled at the end of October, 1971,
periodically tested and emptied in June 1972.  They were then refilled with
new maize in November, 1972, similarly tested and emptied in May, 1973.
The results of these trials demonstrated that both types of silos, if
treated with insecticide, store maize extremely well.  It was determined
that maize dried to a moisture content of 12% and treated with any of a
variety of insecticides could be stored in cement stave silos for at least
six months with average losses of not more than 3 percent.
       During this time, volunteers had been working with local agricultural
officials to popularize and build silos and dryers for interested farmers
who could afford the units which had an average cost of $70-$80 (without
expensive tin roofed shelter).  It was after the I.R.A.T. tests that the
director of the Dahomean Agricultural Service decided to officially adopt
this system, and the National Cereals Commission of Dahomey committed 5 millio
CFA ($20,000) for the credit construction of 100 storage units for individual
farmers each consisting of a 4.5 ton cement stave silo, an earthen dryer,
and a tin-roofed shelter.  The first ten units were built in the region
of Sakete, under the supervision of a technical agent of the Agricultural
Service and a Peace Corps Volunteer.  These completed units were officially
accepted by the Minister of Rural Development and Cooperative Action in
June, 1974, and work has been authorized on construction of another twenty
in the three southern provinces of Dahomey.
       The National Cereals Commission has established criteria for the
100 farmers who are to receive this credit.  The participants must:
       1.  be a farmer
       2.  cultivate at least two hectares (5 acres) of maize per year
       3.  reside in the district where the silo is to be built
       4.  be recognized by local agricultural agents as a progressive
           and cooperative individual
       5.  be willing to sign a contract for the repayment of the loan
       6.  make a 10,000 CFA ($40) cash advance as an indication of
           serious intent.
       The loan is to be paid off in six equal annual payments at 2%
interest.   Payment can be made in cash or the equivalent value of maize
at a pre-determined value of 25 cfa/kg (the average price of maize at the
time of harvest has been from 6 to 10 cfa/kg).
       Over the years, the collaboration has grown between the Peace Corps
and the Agricultural Service and particularly its Division of Crop Protection
which has a supervisory role with respect to the volunteers.
Requests for and assignment of volunteers is handled through these offices.
A volunteer with experience in the program in Dahomey has traditionally
been designated as "Coordinator" by the Dahomean officials and Peace
Corps staff, and he acts as a liaison between the grain storage volunteers
in the field, the Peace Corps staff in Cotonou, and the government agricultural
officials in Porto-Novo.  The Peace Corps, besides furnishing
volunteers, has helped find outside funding for program related projects.
                           Appendix D
The information in this manual is not and can not be complete.  The
information presented here cannot be immediately applicable or appropriate
to all regions or to every storage need.  You may well require
further technical assistance in adapting these materials and others
to your grain storage situation.  Some of that help can come from
books; much, from organizations and people.
The Tropical Products Institute (TPI) may already be a familiar name
to you.   This agency does a great deal to gather and distribute information
worldwide on grain and grain storage problems.  Materials from
the TPI library have been of great value in the preparation of this
Peace Corps and VITA are grateful to TPI for its permission to reprint
that agency's bibliography of materials on the various aspects of farm-level
grain storage.
                     Tropical Products Institute
           G64     Crop storage bibliography
                 (with particular reference to
                 the storage of durable
                 agricultural produce in tropica
                 and sub-tropical countries)
                 Mrs. S.M. Blatchford and A.J. Wye
This bibliography has been produced by the Tropical Products Institute, a British
Government organization which helps developing countries to derive greater benef its
from their renewable resources.
Reproduction of this bibliography, in whole or in part, is gladly permitted provided that
full acknowledgement is given to the Tropical Products Institute, Foreign and
Commonwealth Office, (Overseas Development Administration), and to the authors.
Requests for further information on this subject should be addressed to:
Tropical Stored Products Centre
(Tropical Products Institute)
London Road
Slough SL3 7HL
This bibliography attempts to bring together a selection of the more important publications
dealing with tropical crop storage; it clearly cannot be exhaustive.
Where possible, the prices (at time of publication) and addresses are given for obtaining
publications listed here, excluding scientific papers.  A list of the most common addresses
appears below.
Sales Branch, 101-113.  Pentonville Road, London, N.1.
Tolcarne Drive, Pinner, Middlesex.
Distribution & Sales Section, Via delle Terme di Caracalla, 00100 Rome, Italy.
Superintendent of Documents, U.S. Government Printing Office, Washington D.C. 20402, U.S.A
ANDERSON, J.A. and ALCOCK, A. W. (Eds).
1954             Storage of cereal grains and their products.  St. Paul, Minn:   Amer. Ass.
                Cereal Chem., 1954, ix + 515 pp.  (Out of print:   obtainable from Univ.
                Microfilms, Ann Arbor, Mich., price 10.00 [pounds].  Currently under revision).
BUSVINE, J.R.    Insects and hygiene.   The biology and control of insect pests of medical
1966             and domestic importance.   London:  Methuen and Co., 1966, 2nd rev.
                edn, xi + 467 pp.   Price 5.00 [pounds].
1969             Grain storage.   The role of fungi in quality loss.   Minneapolis, Minn.:
                Univ. Minnesota Press, 1969, vii + 153 pp.  Price $6.50.
COTTON, R.T.     Pests of stored grain and grain products. Minneapolis, Minn: Burgess
1963             Publg Co., 1963, rev. edn, 2 + i + 318 pp.  (Out of print).
MUNRO, J.W.      Pests of stored products.   London:  Hutchinson (The Rentokil Library),
1966             1966, 234 pp.   Price 2.10 [pounds].
1966             Storage of grain.   Moscow:  Izdatel'stva `Kolos', 1966, 3rd edn, 406 pp.
                (Translated into English by Keane, D.M. and edited by Kent, N.L. &
                Freeman, J.A. Boston Spa:   natn. Lending Libr., 1969, 3 volumes, 244,
                287 & 307 pp.   Price 1.25 [pounds] per vol., 3.75 [pounds] the set).
                Quarterly.   Hapur:  Foodgrain Technologists' Research Association of
                India.   Price $3.00 per annum.
                Quarterly.   Oxford:  Pergamon Press.  Price 12.00 [pounds] per annum.
                Biannual.   Bulletin of the Tropical Stored Products Centre (Tropical
                Products Institute).   Free.  (Enquiries to the Tropical Stored Products
                Centre, (TPI), London Road, Slough SL3 7HL, Bucks).
Annual Reports
                Annual reports of the C.F.T.R.I., Mysore - 2, India.   Priced.
                Reports of the Infestation Control Laboratory (Ministry of Agriculture,
                Fisheries & Food).   London:  HMSO.  Priced.
                Annual reports of the Nigerian Stored Products Research Institute, Federal
                Ministry of Trade.   Lagos:  Fed. Minist.  Inform., Printing Div.  Priced.
                Annual reports of the Pest Infestation Laboratory (Agricultural Research
                Council).   London:  HMSO.  Priced.
                Annual reports (up to and including 1967) and then Biennial reports of the
                Tropical Products Institute, (Overseas Development Administration).  May
                be priced.   (Enquiries to the Scientific Secretariat, Tropical Products
                Institute, 56-62 Gray's Inn Road, London WC1X 8LU).
                1970.   Tropical Stored Products Centre.   A Report on the work 1965 - 1966.
                (The work of the Centre prior to 1965 was reported as part of the
                Annual Report `Pest Infestation Research'; from July 1967 it forms a part
                of the Annual and Biennial Reports of the Tropical Products Institute.
                Enquiries to the Tropical Stored Products Centre, (TPI), London Road,
                Slough SL3 7HL, Bucks).
Handbooks, Bulletins, Special Reports
BROWN, W.B.      Fumigation with methyl bromide under gas-proof sheets.  Dep. Sci. Ind.
1959             Res., Pest Infest. Res. Bull. No. 1.  London:   HMSO, 1959, 2nd edn, ii +
                44 pp.   Price 22 1/2p.
1952             Insect infestation of stored food products in Nigeria.  (Report of a survey,
                1948 - 50, and of control measures adopted).  Colonial Res. Publn No. 12.
                London:   HMSO, 1952, 40 pp.   Price 25p.
EASTER, S.S.     (Ed). Preservation of grains in storage.  Papers presented at the international
1947             meeting on infestation of foodstuffs, London, 5 - 12 Aug., 1947.  Wash.,
                D.C.:   Fd. Agric. Org. agric. Stud. No. 2, 1948, 174 pp.  Price $1.50.
FREEMAN, J.A.    Control of pests in stored agricultural products with special reference to
1958             grain.   Report of a survey in North and South America and certain Mediterranean
                countries in 1954 and 1955.  Org. eur. econ. Coop., eur.   Productivity Agency
                Project No. 212, Feb. 1958.  Paris:   OEEC, 1958, 169 pp.  Price 57 1/2p.
                (OEEC Dist. & Sales Serv., 33 Rue de Franqueville, Paris 16e and overseas
FURMAN, D.L.     Suggested guide for the use of insecticides to control insects affecting crops,
1968             livestock, households, stored products, forests and forest products.  U.S.
                Dep. Agric., agric. Res. Serv., agric. Handbk No. 331, 1968, rev. edn, xvi +
                273 pp + 2 app.   Price $1.50.
HALL, D.W.       Handling and storage of food grains in tropical and sub-tropical areas.  FAO
1970             agric.   Dev. Paper No. 90.  Rome:  UNFAO, 1970, xiv + 350 pp.
                Price US $6 (2.40 [pounds]).
1963             Common insect pests of stored food products.  A guide to their identification.
                Econ. Ser. Brit. Museum (nat. Hist.), No. 15. London:  British Museum,
                1963, 4th edn, vi + 61 pp. Price 17 1/2p.
HOLMAN, L.E.     (Compiler).   Aeration of grain in commercial storages. U.S. Dep. Agric.,
1960             Mktg Res. Rep. No. 170, 1960 (revised and reprinted Sept. 1966), 46 pp.
                Price 35 [cents].
HUGHES, A.M.     The mites of stored food.   Tech. Bull. Minist. Agric. Fish. Fd, No. 9, 1961,
1961             vi + 287 pp. London:   HMSO.  Price 87%p.
ORGANISATION.       Report of the international conference on the protection of stored products,
1968             Lisbon 27 - 30 Nov. 1967.   EPPO Publications, Ser. A, No. 46-E. Paris:
                EPPO, 1968, 171 pp. Price 1.65 [pounds]. (EPPO, 1 rue le Notre, Paris).
ORGANIZATION.       Report of the working party on Stored Products of Tropical Origin (Hamburg,
1969             5 - 6 Nov. 1968).   EPPO Publications, Ser. A, No. 51-E. Paris:  EPPO, 1969,
                38 pp + 7 tables.  Price 50p. (EPPO, 1 rue le Notre, Paris).
ORGANISATION.       Report of the Working Party on Stored Products of Mediterranean Origin
1970             (Lisbon, 13 - 14 March, 1969).  EPPO Publications, Ser. A, No. 56. Paris:
                EPPO, 1970, 85 + xxx pp.   Price unknown.   (EPPO, 1 rue le Notre, Paris).
1968             The toxicity of contact insecticides to seed-infesting insects.  Series No. 6.
                Tests with bromophos on maize.  S. Afr. Dep. Agric., tech. Serv., tech.
                Commun. No. 84. Pretoria:   Government Printer, 1968, 9 pp.
1958             Protection of stored seeds in Egypt.  Bull. Minist. Agric. Egypt, Ext. Dep.,
                No. 295. Cairo:   General Organization for Government Printing Offices,
                1958, 16 pp.
LAHUE, D.W.      Evaluation of several formulations of malathion as a protectant of grain
1969             sorghum against insects - in small bins.  U.S. Dep. Agric., agric. Res. Serv.,
                Mktg Res. Rep. No. 828, 1969, iv + 19 pp. Price 20 [cents].
LAHUE, D.W.      Evaluation of malathion, diazinon, a silica aerogel and a diatomaceous
1970             earth as protectants on wheat against lesser grain borer attack ... in small
                bins.   U.S. Dep. Agric., agric. Res. Serv., Mktg Res. Rep. No. 860, 1970,
                iv + 12 pp.
LOCHNER, E.H.W. Safe storage of food grains in the Republic of South Africa.   S. Afr. Dep.
1963             Agric., tech. Serv., tech. Commun. No. 13. Pretoria:  Government Printer,
                1963, ii + 45 pp.
LOCHNER, E.H.W. Fumigation of maize in railway trucks in transit to the ports.   (In Africaans
1964             with English Summary).   S. Afr. Dep. Agric., tech. Serv., tech. Commun.
                No. 25. Pretoria:   Government Printer, 1964, ii + 62 pp.
1961             Prevention and control of infestation of stored grain by insect pests and
                rodents.   Prepared jointly by the Storage and Infestation.Division (Mktg
                Dept, Minist. Trade and Ind.) and Plant Protection Division (Minist. Agric.
                and Lands).   Kingston, Jamaica:   Govt Printer, 1961, iii + 57 pp.
MONRO, H.A.U.    Manual of fumigation for insect control.  F.A.0. agric. Studies, No. 79.
1971             Rome:   FAO, 1971, xii + 381 pp. Second edn, revised.   Price 2.80 [pounds].
ORDISH, G.       (Gen. Ed). Pest control in groundnuts.  PANS Manual No. 2. London:
1967             Minist.   Overseas Dev., trop. Pestic. Res. H.Q. & Inf. Unit, 1967, iv + 138 pp.
                Price 45P.   (56-62 Gray's Inn Rd, London, WC1X8LU).
PREVETT, P.F.    An investigation into storage problems of rice in Sierra Leone.  Colonial
1959             Res. Studies, No.28.   London:  HMSO, 1959, 52 pp.
RANSOM, W.H.     Buildings for the storage of crops in warm climates.  Dep. sci. ind. Res.
1960             Trop. Building Studies, No. 2. London:  HMSO, 1960, 24 pp. Price 22 1/2p.
SALMOND, K.F.    Investigations into grain storage problems in Nyasaland with special
1957             reference to maize (Zea mays L.).  Colonial Res. Publn No. 21.   London:
                HMSO, 1957, 49 pp. Price 22 1/2p.
SMITH, C.V.      Meteorology and grain storage.   Tech. Note U.N. Wld met. Org., No. 101
1969             (WMO No. 243 TP 133). Geneva:   Secretariat of World Meteorological
                Organisation, 1969, xvi + 47 pp. Price 1.00 [pounds].
STEELE, B.       (Gen. Ed.). Pest control in rice.   PANS Manual No. 3. London:   Minist.
1970             Overseas Dev. trop. Pestic. Res. H.Q. & Inf. Unit, 1970, ii + 270 pp.
                Price 62 1/2p.   (56-62 Gray's Inn Rd, London WC1 X8LU).
1968             Improved storage and its contribution to world food supplies.  Chapter 4
                in `State of Food and agriculture, 1968', pp 115 - 143.  Rome:   FAO,
                1968, 205 pp. Price $5.75 or 2.30 [pounds].
1969             Crop Storage.   Technical Report No. 1 of the Food Research and Development
                Unit, Accra, Ghana.   Prepared for the Government of Ghana by FAO
                acting as executing agency for the United Nations Development Programme,
                based on the work of J. Rawnsley.  PL:SF/GHA 7.   Rome:  FAO, 1969,
                ix + 89 pp + 7 app.
1958             Stored grain pests.   U.S. Dep. Agric. Fmrs Bull. No. 1260, 1958, rev.,
                46 pp. Price 25 [cents].
WOGAN, G.N.      (Ed.).  Mycotoxins in foodstuffs.  Proceedings of a symposium at Massachusetts
1965             Inst. Technol., March 1964.   Cambridge, Mass:   Mass. Inst. Technol.
                Press, 1965, xii + 291 pp. Price 3.75 [pounds].
1970             Food storage manual.   (Prepared by the Tropical Stored Products Centre,
                Ministry of Overseas Development).  Rome:   FAO, 1970, 3 vols, 820 pp.
                Price $18.
Advisory Leaflets
1969             C.M.I. descriptions of pathogenic fungi and bacteria.  Set 22, sheets 211 - 220.
                Kew:   Commonw. Mycol. Inst., 1969. Price 25p. (Commonw.
                Mycol. Inst., Ferry Lane, Kew, Surrey).
1967             Methods for sampling oilseeds.  Br. Stand. No. 4146, 1967, 16 pp.  Price 30p.
1968             Methods of test for cereals and pulses.  Part 2.   Determination of moisture
                content of cereals and cereal products (basic reference method).  Br. Stand.
                No. 4317, Part 2, 1968, 12 pp. Price 25p.
1968             Methods of test for cereals and pulses.  Part 4.   Determination of impurities
                in pulses.   Br. Stand. No. 431 7, Part 4, 1968, 7 pp.  Price 20p.
1969             Methods for sampling cereals (as grain).  Br. Stand. No. 4510, 1969, 19 pp.
                Price 50p.
1969             Methods for sampling pulses.   Br. Stand. No. 4511, 1969, 16 pp. Price 40p.
1969             Recommended common names for pesticides.  Br. Stand. No. 1831, 1969,
                4th rev., 107 pp.   Price 2.00 [pounds].
1968             Mechanical seed cleaning and handling.  U.S. Dep. Agric., agric. Res. Serv.
                (in conj. w. Oregon agric. Exp. Stn), agric. Handbk No. 354, 1968, 56 pp.
                Price 55 [cents].
1966             Fumigation with the liquid fumigants carbon tetrachloride, ethylene
                dichloride and ethylene dibromide.  Precautionary measures.   London:
                HMSO, 1966, rev. edn, i + 8 pp.  Price 71/2p.
1968             Heating of grain in store.   Minist. Agric. Fish. Fd, Adv. Leafl. No. 404,
                1968, rev., 6 pp.   Single copies free.
1968             Insect pests in food stores.   Minist. Agric. Fish. Fd, Adv.`Leafl. No. 483,
                1968, rev., 8 pp.   Single copies free.
1969             Fumigation with ethylene oxide.  Precautionary measures, 1969.  London:
                HMSO, 1969, 8 pp. Price 9p.
1969             Guide lines for mold control in high-moisture corn.  U.S. Dep. Agric., Fmrs
                Bull. No. 2238, 1969, rev., 16 pp. Price 10 [cents].
1969             Controlling insects in farm-stored grain.  U.S. Dep. Agric., Leaff. No. 553,
                1969, 8 pp. Price 10 [cents].
Scientific Papers
A full list of papers published by staff of the Tropical Stored Products Centre is available on
request from the TSPC, (TPI), London Road, Slough SL3 7HL, Bucks).
1957             Panorama actual dos problemas fitossanitarios dos produtos armazenados
                em Africa.   (Comprehensive survey of phytosanitary problems of stored
                products in Africa).   Garcia de Orta, 5 (4), 675 - 699.
ASHMAN, F.       The chemical control of stored food insect pests in Kenya.  J. agric. vet.
1963             Chem., 4 (2), 44-48.
ASHMAN, F.       An assessment of the value of dilute dust insecticides for the protection of
1966             stored maize in Kenya.   J. appl. Ecol., 3(1), 169 - 179.
ASHMAN, F.       Inspection methods for detecting insects in stored produce.  Trop. stored
1966             Prod. Inf., (12), 481 - 494.
1969             An instrument for detecting insects within food grains.  Milling, 151 (3),
                32, 34 & 36.
1965             The fauna of stored products in U.A.R.  Bull. Soc. ent. Egypte, 49, 221 - 232.
BAILEY, S.W.     Airtight storage of grain, its effects on insect pests.  II.   Calandra oryzae
1956             (small strain).   Aust. J. agric. Res., 7 (1), 7 - 19.
BAILEY, S.W.     Airtight storage of grain, its effects on insect pests. III.  Calandra oryzae
1957             (large strain).   Aust. J. agric. Res., 8 (6), 595 - 603.
BAILEY, S.W.     The effects of percussion on insect pests of grain.  J. econ. Ent., 55 (3),
1962             301 - 305.
BAILEY, S.W.     Airtight storage of grain - its effect on insect pests. IV.  [\IRhyzopertha
1965             dominica (F.) and some other Coleoptera that infest stored grain.
                J. stored Prod. Res., 1 (1), 25 - 33.
BARNES, J.M.     Pesticide residues as hazards.  PANS, 15 (1), 2 - 8.
BREESE, M.H.     The infestibility of stored paddy by Sitophilus sasakii (Tak.) and
1960             Rhyzopertha dominica (F.).   Bull. ent. Res., 51 (3), 599 - 630.
BREESE, M.H.     Studies on the oviposition of Rhyzopertha dominica (F.) in rice and paddy.
1963             Bull. ent. Res., 53 (4), 621 - 637.
BURRELL, N.J.      The chilled storage of grain.   Ceres, (5), 15-20.
1960               Da occorrencia de algunas pragas de produtos ultramarinos en poroes de
                  navios mercantes (Carreira da Guine).  (Occurrence and distribution of
                  some pests of stored products in ships' holds of cargo ships of the Guinea
                  Line).   Garcia de Orta, 8 (1), 47-57.
CASWELL, G.H.      The infestation of cowpeas in the Western Region of Nigeria.  Trop. Sci., 3
1961               (4), 154 - 158.
1960               Effect of moisture content on germination and growth of fumigated maize
                  grain.   Emp. J. exp. Agric., 28, 139 - 149.
1965               Deterioration of stored grains by fungi.  A. Rev. Phytopath., 3, 69 - 84.
1963               Pathology of stored seeds.   Proc. int. Seed Test. Ass., 28, 701 - 711.
CLARKE, J.H.       Fungi in stored products.   Trop. stored Prod. Inf., (15), 3 - 14.
COAKER, T.H.       'Insack' treatment of maize with insecticide for protection against storage
1959               pests in Uganda.   E. Afr. agric. J., 24 (4), 244 - 250.
COLLINGS, H.       Hermetic sealing of a stack of maize with bituminous roofing felt.
1960               Trop. Agric., Trin., 37 (1), 53 - 60.
COURSEY, D.G.      Yam storage.   I : a review of yam storage practices and of information on
1967               storage losses.   J. stored Prod. Res., 2 (3), 229 - 244.
COVENEY, R.D.      Sacks for the storage of food grains.  Trop. stored Prod inf.,(17), 3-22.
CRANHAM, J.E.      Insect infestation of stored raw cocoa in Ghana.  Bull. ent. Res., 51 (1),
1960               203 - 222.
1967               Moisture content/relative humidity equilibria of tropical stored produce.
                  Part 3. Legumes, spices and beverages.   Trop. stored Prod. Inf., (13), 15 - 34.
DAVIES, J.C.       Aluminium phosphide for bulk grain fumigation in Uganda.  E. Afr. agric.
1958               J., 24 (2), 103 - 105.
DAVIES, J.C.       A note on the control of bean pests in Uganda.  E. Afr. agric. J., 24 (3),
1959               174 - 178.
DAVIES, J.C.       Coleoptera associated with stored products in Uganda.  E. Afr. agric. J., 25
1960               (3), 199 - 201.
DAVIES, J.C.       Storage of maize in a prefabricated aluminium silo in tropical conditions.
1960               E. Afr. Agric. J., 25 (4), 225 - 228.
DAVIES, J.C.       Experiments on the crib storage of maize in Uganda.  E. Afr. agric. J., 26
1960               (1), 71 - 75.
1969               Drying or anaerobically preserving small lots of grain for seed or food.
                  Agron. J., 61 (6), 913 - 919.
ELDER, W.B.        CSIRO develops aeration system for farm-stored grain.  Pwr Fmg Bett. Fmg
1969               Dig., 78 (10), 10 - 13.
FULLERTON, R.L.    Low-cost farm buildings for storage and equipment housing in Ghana.
1968               Ghana J. agric. Sci., 1 (2), 165 - 170.
GILES, P.H.        The storage of cereals by farmers in Northern Nigeria.  Trop. Agric., Trin.,
1964               41 (3), 197 - 212.
GILES, P.H.        Control of insects infesting stored sorghum in Northern Nigeria.  J. stored
1965               Prod. Res., 1 (2), 145 - 158.
GILES, P.H.        Maize storage: the problem of today.  Trop. stored Prod. Inf., (14), 9 - 19.
GILES, P.H.        Observations in Kenya on the flight activity of stored products insects,
1969               particularly Sitophilus zeamais Motsch.  J. stored Prod. Res., 4 (2), 317 - 329.
1966               Radiation disinfestation of grain and seeds.  Proc. Symp. Food Irradiation,
                  Karlsruhe, 1966, pp 473 - 488.  Vienna : Int. Atomic Energy Agency.
1968               Changes in the microfloral composition of moist sorghum stored under
                  hermetic conditions.   Trop. Sci., 10 (2), 107 - 114.
GRAHAM, W.M.       Warehouse ecology studies of bagged maize in Kenya.  I. The distribution
1970               of adult Ephestia (Cadra) cautella (Walker) (Lepidoptera, Phycitidae).
                  II. Ecological observations of an infestation by E. cautella. III. Distribution
                  of the immature stages of E. cautella. IV. Reinfestation following
                  fumigation with methyl bromide gas.   J. stored Prod. Res., 6 (2): I, 147 - 155;
                  II, 157 - 167; III, 169 - 175; IV, 177 - 180.
GREEN, A.A.        The protection of dried sea-fish in South Arabia from infestation by
1967               Dermestes frischii Kug.  (Coleoptera, Dermestidae).  J. stored Prod. Res.,
                  2 (4), 331 - 350.
HALL, D.W.         Prevention of waste of agricultural produce during handling, storage and
1968               transportation.   Trop. stored Prod. Inf., (15), 15 - 23.
HALL, D.W.         Food storage in the developing countries.  J.R. Soc. Arts, 117 (5156),
1969               562 - 579.
HALLIDAY, D.       Build-up of free fatty acid in Northern Nigerian groundnuts.  Trop. Sci., 9
1967               (4), 211 - 237.
HAYWARD, L.A.W.    Infestation control in stored groundnuts in Northern Nigeria.  Wld Crops,
1963               15 (2), 63 - 67.
HOWE, R.W.         Entomological problems of food storage in Northern Nigeria.  Bull. ent.
1952               Res., 43 (1), 111 - 144.
HOWE, R.W.         A summary of estimates of optimal and minimal conditions for population
1965               increase of some stored products insects.  J. stored Prod. Res., 1 (2), 177 - 184.
HOWE, R.W.         Losses caused by insects and mites in stored foods and feeding stuffs.  Nutr.
1965               Abstr. Rev., 35, 285 - 293.
1964               Some laboratory observations on the rates of development, mortality and
                  oviposition of several Bruchidae breeding in stored pulses.  Bull. ent. Res.,
                  55 (3), 437 - 477.
HYDE, M.B.         Hazards of storing high-moisture grain in airtight silos in tropical countries.
1969               Trop. stored Prod. Inf., (18), 9 - 12.
JOFFE, A.          Moisture migration in horizontally stored bulk maize: influence of graininfesting
1958               insects under South African conditions.  S. Afr. J. agric. Sci., 1
                  (2), 175 - 193.
JOFFE, A.          The effect of physical disturbance or 'turning' of stored maize on the
1963               development of insect infestation.  I. Grain elevator studies.  S. Afr. J.
                  agric. Sci., 6, 55 - 64.
1959               Storage and preservation of fatty foods.  Food Sci., Mysore, 8, 257 - 262.
KHALIFA, A.        On open-air and underground storage in the Sudan.  Bull. Soc. ent. Egypte,
1960               53 (44), 129 - 142.
KHALIFA, A.        The relative susceptibility of some varieties of sorghum to Trogoderma
1962               attack.   Emp. J. exp. Agric., 30 (118), 133 - 136.
KOCKUM, S.         Protection of cob maize stored in cribs.  E. Afr. agric. J., 19 (2), 69 - 173.
KOCKUM, S.         Control of insects attacking maize on the cob in crib stores.  E. Afr. agric.
1958               J., 23 (4), 275 - 279.
1954               Experiments in the use of insecticides for the protection of grains in storage.
                  Bull. ent. Res., 45 (2), 295 - 311.
McFARLANE, J.A.    An annotated record of Coleoptera, Lepidoptera, Hemiptera and Hymenoptera
1963               associated with stored produce in Jamaica.  Trop. Agric., Trin., 40 (3), 211-216
McFARLANE, J.A.    The productivity and rate of development of Sitophilus oryzae (L.) (Coleoptera,
1968               Curculionidae) in various parts of Kenya.  J. stored Prod. Res., 4 (1), 31 - 51.
McFARLANE, J.A.    Stored products insect control in Kenya.  Trop. stored Prod. Inf., (18), 13 - 23
McFARLANE, J.A.    Treatment of large grain stores in Kenya with dichlorvos slow-release strips
1970               for the control of Cadra cautella.  J. econ. Ent., 63 (1), 288 - 292.
MACKAY, P.J.       Theory of moisture in stored produce.  Trop. stored Prod. Inf.,   13)., 9 - 14.
1964               Toxicity of calcium phosphate to some pests of stored grain.  Nature,
                  Lond., 202 (4939), 1359 - 1360.
1961               Pre-harvest prophylaxis for infestation control in stored food grains.
                  Nature, Lond., 192 (4800), 375 - 376.
1959               Insecticidal effects of activated charcoal and clays.  Nature, Lond, 184
                  (4693), 1165 - 1166.
1963               Some aspects of the problem of bulk storage of foodgrains in India.
                  Wld Rev. Pest Control, 2 (2), 25 - 35.
1969               Fungi associated with [\i]Sorghum vulgare under different storage conditions
                  in India.   PANS, 15 (3), 365 - 367.
1963               Fumigation of insects.  A. Rev. Ent., 8, 239 - 264.
PARKIN, E.A.       The protection of stored seeds from insects and rodents.  Proc. Int. Seed
1963               Test. Ass., 28 (4), 893 - 909.
PARKIN, E.A.       The onset of insecticide resistance among field populations of stored product
1965               insects.   J. stored Prod. Res., 1 (1) 3 - 8.
1957               Effect of insect infestation on stored grain: II. Studies on husked, handpounded,
                  milled raw rice and parboiled milled rice.  J. Sci. Fd Agric., 8 (9),
                  512 - 516.
1954               Effect of insect infestation on stored wheat.  I. Studies on soft wheat.
                  J. Sci. Fd Agric., 5 (1), 51 - 54.
PIXTON, S.W.       Moisture content - its significance and measurement in stored products.
1967               J. stored Prod. Res., 3 (1), 35 - 47.
PIXTON, S.W.       A possible rapid method of determining the moisture content of high-moisture
1970               grain.   J. Sci. Fd Agric., 21 (9), 465 - 467.
POINTEL, J-G.      Contribution a la conservation du niebe , du vouandzou, du mais, des
1968               arachides et du sorgho. (Contribution to the preservation of cowpeas,
                  Voandzeia subterranea (Bambarra groundnut), maize, groundnuts and
                  sorghum).   Agron. trop., Nogent, 23 (9), 982 - 986.
POINTEL, J-G.      Essai et enquete sur greniers a mais togolais. (A trial and survey on
1969               Togolese maize granaries).   Agron. trop., Nogent, 24 (8), 709 - 718.
1965               Pusa bin for grain storage   Indian Fmg, 15 (1), 14 - 16.
PREVETT, P.F.      A study of rice storage under tropical conditions.  J. agric. Engng Res., 4
1959               (3), 243 - 254.
PREVETT, P.F.      The distribution of insects in stacks of bagged groundnuts in Northern
1964               Nigeria.   Bull. ent. Res., 54 (4), 689 - 713.
1970               Irradiation of early instars of the Angoumois Grain Moth.  J. econ. Ent.,
                  63 (4), 1241 - 1247.
RHYNEHART, T.      The control of insects infesting groundnuts after harvest in the Gambia:
1960               IV.   The practical application of control measures.   Trop. Sci., 2 (3), 134 - 139.
ROBERTSON, J.V.    Trials with small capacity grain silos in Dar es Salaam, Tanzania.  E. Afr.
1968               agric. for J., 34 (2), 263 - 276.
ROWLANDS, D.G.     The metabolism of contact insecticides in stored grains.  Residue Rev., 17,
1967               105 - 177.
1965               Storage structures for large scale handling and preservation of food grain.
                  Bull. Grain Tech., 3 (2), 62 - 69.
1968               Protection of marketable grain.  Bull. Grain Tech., 6 (1), 16 - 20.
1965               Studies on the large scale storage of food grains in India.  Part II. Studies
                  on the relative suitability of cement concrete and aluminium bins for
                  storing wheat.   Bull. Grain Tech., 3 (4), 135 - 141.
1967               Studies on the large scale storage of food grains in India.  Part III. Studies
                  on the insect and temperature fluctuations in bag storage of wheat.   Bull.
                  Grain Tech., 5 (1), 3 - 11.
SODERSTROM, E.L.  Effectiveness of green electroluminescent lamps for attracting stored-product
1970               insects.   J. econ. Ent., 63 (3), 726 - 731.
SOUTHGATE, B.J.    Plastics films for the bulk storage of food.  Plast. Inst. Trans. & J., 33
1965               (103), 11 - 15.
1960               Germination of cereal, sorghum and small legume seeds after fumigation
                  with hydrogen phosphide.  J. econ. Ent., 53 (1), 1 - 4.
1961               Effect of methyl bromide and hydrocyanic acid fumigation on the germination
                  of corn seed.   J. econ. Ent., 54 (8), 764 - 770.
SWAINE, G.         Trials on the underground storage of maize of high moisture content in
1957               Tanganyika.   Bull. ent. Res., 48 (2), 397 - 406.
1960               Effect of insect infestation on stored field bean (Dolichos lablab) and
                  black gram (Phaseolus mungo).  Fd Sci., Mysore, 9, 79 - 82.
1958               Effect of insect infestation on stored grain: III. Studies on Kaffir corn
                  (Sorghum vulgare).   J. Sci. Fd Agric., 9 (12), 837 - 839.
WATTERS, F.L.      Effects of grain moisture content on residual toxicity and repellency of
1959               malathion.   J. econ. Ent., 52 (1), 131 - 134.
WATTERS, F.L.      Physical methods of insect control.   Proc. Ent. Soc. Manitoba, 21,
1965               18 - 27.
WATTERS, F.L.      An appraisal of gamma irradiation for insect control in cereal foods.
1968               Manitoba Ent., 2, 37-45.
1970               Polythene sacks for the control of insects in grain.  J. stored Prod. Res.,
                  6 (1), 97 - 101.
WRIGHT, F.N.       New storage, transportation and handling techniques for tropical agricultural
1965               produce.  Congr. Prot. Cult. Trop., Marseilles, 1965, pp 93 - 98.   Marseilles:
                  Chambre de Commerce et d'Industrie.
1962               The potential uses of plastics for storage with particular reference to rural
                  Africa.   Trop. Sci., 4 (2), 74 - 81.
                        Conversion Tables
                    Simple methods are given here for
                  converting English and metric units
                  of measurement.   Following these is
                  a series of useful conversion tables
                  for units of area, volume, weight,
                  pressure and power.
  The chart in Figure 3 is useful
for quick conversion from meters and
centimeters to feet and inches, or
vice versa.   For more accurate results
and for distances greater than 3 meters,           Equations:
use either the tables in Figure 2 or
the equations.                                        1 inch = 2.54cm
                                                     1 foot = 30.48cm
  The chart in Figure 3 has metric divisions                = 0.3048m
of one centimeter to three meters,                   1 yard = 91.44cm
and English units in inches and feet                        = 0.9144m
to ten feet.   It is accurate to about                 1 mile = 1.607km
plus or minus one centimeter.                               = 5280 feet
                                                     1cm    = 0.3937 inches
Example:                                              1m      = 39.37 inches
                                                            = 3.28 feet
  An example will explain how to use                  1km     = 0.62137 miles
the tables.   Suppose you wish to find                        = 1000 meters
how many inches are equal to 66cm.  On
the "Centimeters into Inches" table look
down the leftmost column to 60cm and then
right to the column headed 6cm.  This
gives the result, 25.984 inches.
                              Inches into centimeters              FIGURE 2
                               (1 in. = 2.539977 cm.)
inches     0      1        2         3         4        5         6         7        8         9
  0     cm.      2.54      5.08     7.62    10.16     12.70    15.24    17.78     20.32    22.86
 10    25.40    27.94     30.48    33.02    35.56     38.10    40.64    43.18     45.72    48.26
 20    50.80    53.34     55.88    58.42    60.96     63.50    66.04    68.58     71.12    73.66
 30    76.20    78.74     81.28    83.82    86.36     88.90    91.44    93.98     96.52    99.06
 40   101.60   104.14    106.68   109.22   111.76    114.30   116.84   119.38    121.92   124.46
 50   127.00   129.54    132.08   134.62   137.16    139.70   142.24   144.78    147.32   149.86
 60   152.40   154.94    157.48   160.02   162.56    165.10   167.64   170.18    172.72   175.26
 70   177.80   180.34    182.88   185.42   187.96    190.50   193.04   195.58    198.12   200.66
 80   203.20   205.74    208.28   210.82   213.36    215.90   218.44   220.98    223.52   226.06
 90   228.60   231.14    233.68   236.22   238.76    241.30   243.84   246.38    248.92   251.46  
                              Centimeters into inches
                               (1 cm. = 0.3937 in.)
cm.      0        1        2         3        4        5         6         7        8         9
  0   inches    0.394     0.787    1.181    1.575     1.969    2.362    2.756     3.150    3.543
 10    3.937    4.331     4.724    5.118    5.512     5.906    6.299    6.693     7.087    7.480
 20    7.874    8.268     8.661    9.055    9.449     9.843   10.236   10.630    11.024   11.417
 30   11.811   12.205    12.598   12.992   13.386    13.780   14.173   14.567    14.961   15.354
 40   15.748   16.142    16.535   16.929   17.323    17.717   18.110   18.504    18.898   19.291
 50   19.685   20.079    20.472   20.866   21.260    21.654   22.047   22.441    22.835   23.228
 60   23.622   24.016    24.409   24.803   25.197    25.591   25.984   26.378    26.772   27.165
 70   27.559   27.953    28.346   28.740   29.134    29.528   29.921   30.315    30.709   31.102
 80   31.496   31.890    32.283   32.677   33.071    33.465   33.858   34.252    34.646   35.039
 90   35.433   35.827    36.220   36.614   37.008    37.402   37.795   38.189    38.583   38.976
<FIGURE 140>

51ap199.gif (600x600)

  The chart in Figure 5 converts pounds
and ounces to kilograms and grams or
vice versa.   For weights greater than
ten pounds, or more accurate results,
use the tables (Figure 4) or conversion
equations.   See "Length Conversion,"
Figure 2, for an example of the use of
the tables.
  On the chart, notice that there are
sixteen divisions for each pound to
represent ounces.  There are 100 divisions
only in the first kilogram, and
each division represents ten grams.
The chart is accurate to about plus
or minus twenty grams.
  1 ounce = 28.35 grams
  1 pound = 0.4536 kilograms
  1 gram = 0.03527 ounce
  1 gram = 2.205 pounds
                              Kilograms into pounds
                              (1 kg. = 2.20463 lb.)
 kg.     0        1         2         3        4         5         6        7         8         9
  0    lb.       2.20      4.41     6.61     8.82     11.02    13.23    15.43     17.64    19.84
 10    22.05    24.25     26.46    28.66    30.86     33.07    35.27    37.48     39.68    41.89
 20    44.09    46.30     48.50    50.71    52.91     55.12    57.32    59.53     61.73    63.93
 30    66.14    68.34     70.55    72.75    74.96     77.16    79.37    81.57     83.78    85.98
 40    88.19    90.39     92.59    94.80    97.00     99.21   101.41   103.62    105.82   108.32
 50   110.23   112.44    114.64   116.85   119.05    121.25   123.46   125.66    127.87   130.07
 60   132.28   134.48    136.69   138.89   141.10    143.30   145.51   147.71    149.91   152.12
 70   154.32   156.53   158.73   160.94    163.14   165.35   167.55    169.76   171.96   174.17
 80   176.37   178.58    180.78   182.98   185.19    187.39   189.60   191.80    194.01   196.21
 90   198.42   200.62    202.83   205.03   207.24    209.44   211.64   213.85    216.05   218.26
                              Pounds into kilograms
                             (1 lb. =   0.45359 kg.)
 lb.    0        1         2         3        4         5         6        7         8         9
  0   kg.       0.454     0.907    1.361    1.814     2.268    2.722    3.175     3.629    4.082
 10    4.536    4.990     5.443    5.897    6.350     6.804    7.257    7.711     8.165    8.618
 20    9.072    9.525     9.979   10.433   10.886    11.340   11.793   12.247    12.701   13.154
 30   13.608   14.061    14.515   14.969   15.422    15.876   16.329   16.783    17.237   17.690
 40   18.144   18.597    19.051   19.504   19.958    20.412   20.865   21.139    21.772   22.226
 50   22.680   23.133    23.587   24.040   24.494    24.948   25.401   25.855    26.308   26.762
 60   27.216   27.669    28.123   28.576   29.030    29.484   29.937   30.391    30.844   31.298
 70   31.751   32.205    32.659   33.112   33.566    34.019   34.473   34.927    35.380   35.834
 80   36.287   36.741    37.195   37.648   38.102    38.555   39.009    39.463   39.916    40.370
 90   40.823   41.277    41.730   42.184   42.638    43.091   43.545   43.998    44.452   44.906
  The chart in Figure 1 is useful for
quick conversion from degrees Celsius
(Centigrade) to degrees Fahrenheit and
vice versa.   Although the chart is fast
and handy, you must use the equations
below if your answer must be accurate
to within one degree.
Degrees Celsius = 5/9 x (Degrees
  Fahrenheit -32)
Degrees Fahrenheit = 1.8 x (Degrees
  Celsius) +32
  This example may help to clarify the
use of the equations; 72F equals how
many degrees Celsius?
  72F = 5/9 (Degrees F -32)
  72F = 5/9 (72 -32)
  72F = 5/9 (40)
  72F = 22.2C
  Notice that the chart reads 22C, an
error of about 0.2C.
                              Conversion Tables
Units of Area
1 Square Mile         = 640 Acres                   = 2.5899 Square Kilometers
1 Square Kilometer   = 1,000,000 Square Meters    = 0.3861 Square Mile
1 Acre                =  43,560 Square Feet
1 Square Foot         =  144 Square Inches         = 0.0929 Square Meter
1 Square Inch         =  6.452 Square Centimeters
1 Square Meter        =  10.764 Square Feet
1 Square Centimeter  =   0.155 Square Inch
Units of Volume
1.0 Cubic Foot        = 1728 Cubic Inches           = 7.48 U.S. Gallons
1.0 British Imperial Gallon = 1.2 U.S. Gallons
1.0 Cubic Meter       = 35.314 Cubic Feet           = 264.2 U.S. Gallons
1.0 Liter             = 1000 Cubic Centimeters      = 0.2642 U.S. Gallons
Units of Weight
1.0 Metric Ton        = 1000 Kilograms              = 2204.6 Pounds
1.0 Kilogram          = 1000 Grams                  = 2.2046 Pounds
1.0 Short Ton         = 2000 Pounds
                             Conversion Tables
Units of Pressure
1.0 Pound per square inch             = 144 Pounds per square foot
1.0 Pound per square inch             = 27.7 Inches of Water*
1.0 Pound per square inch             = 2.31 Feet of Water*
1.0 Pound per square inch             = 2.042 Inches of Mercury*
1.0 Atmosphere                         = 14.7 Pounds per square inch (PSI)
1.0 Atmosphere                         = 33.95 Feet of Water
1.0 Foot of Water = 0.433 PSI         = 62.355 Pounds per square foot
1.0 Kilogram per square centimeter    = 14.223 Pounds per square inch
1.0 Pound per square inch             = 0.0703 Kilogram per square centimeter
(*) at 62 degrees Fahrenheit (16.6 degrees Celsius)
Units of Power
1.0 Horsepower (English)              = 746 Watts = 0.746 Kilowatt (KW)
1.0 Horsepower (English)              = 550 Foot Pounds per second
1.0 Horsepower (English)              = 33,000 Foot Pounds per minute
1.0 Kilowatt (KW) = 1000  Watts        = 1.34 Horsepower (HP) English
1.0 Horsepower (English)              = 1.0139 Metric Horsepower (cheval-vapeur)
1.0 Metric Horsepower                 = 75 Meters X Kilogram/Second
1.0 Metric Horsepower                 = 0.736 Kilowatt = 736 Watts