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                              TECHNICAL PAPER #7
                          UNDERSTANDING COMPOSTING
                       J. Walter Fitts & Jerry B. Fitts
                              Technical Reviewers
                       Ellen M. Craft & David J. Graham
                       1600 Wilson Boulevard, Suite 500
                         Arlington, Virginia 22209 USA
                     Tel: 703/276-1800 . Fax 703/243-1865
                           Understanding Composting
                             ISBN: 0-86619-207-7
                 [C] 1984, Volunteers in Technical Assistance
This paper is one of a series published by Volunteers in Technical
Assistance to provide an introduction to specific state-of-the-art
technologies of interest to people in developing countries.
The papers are intended to be used as guidelines to help
people choose technologies that are suitable to their situations.
They are not intended to provide construction or implementation
details. People are urged to contact VITA or a similar organization
for further information and technical assistance if they
find that a particular technology seems to meet their needs.
The papers in the series were written, reviewed, and illustrated
almost entirely by VITA Volunteer technical experts on a purely
voluntary basis. Some 500 volunteers were involved in the production
of the first 100 titles issued, contributing approximately
5,000 hours of their time. VITA staff included Leslie Gottschalk
and Maria Giannuzzi as editors, Julie Berman handling typesetting
and layout, and Margaret Crouch as project manager.
VITA Volunteers Dr. J. Walter Fitts and Jerry B. Fitts, the
authors of this paper, are agronomists with Agro Services International,
Inc., an agricultural consulting firm. They have both
published widely in the fields of agronomy and soil science. Dr.
J. Walter Fitts was formerly the head of the Soil Department at
North Carolina State University, and was director of the International
Soil Fertility Evaluation Program at North Carolina
State University for several years. Jerry B. Fitts was formerly
with the Soil Science Departments at North Dakota State University
and the University of Minnesota. VITA Volunteer Ellen M.
Craft, a reviewer of this paper, is a research associate with the
Department of Agronomy, Iowa State University. She has taught
upper level courses in agronomy there. VITA Volunteer David J.
Graham, also a reviewer of this paper, is Special Assistant to
the Director, Office of Environmental Engineering and Technology,
Office of Research & Development, Environmental Protection Agency
in Washington, D.C. The laboratories at EPA where Mr. Graham
works have been involved in composting research for over 10
VITA is a private, nonprofit organization that supports people
working on technical problems in developing countries. VITA offers
information and assistance aimed at helping individuals and
groups to select and implement technologies appropriate to their
situations. VITA maintains an international Inquiry Service, a
specialized documentation center, and a computerized roster of
volunteer technical consultants; manages long-term field projects;
and publishes a variety of technical manuals and papers.
                           UNDERSTANDING COMPOSTING
            By VITA Volunteers J. Walter Fitts and Jerry B. Fitts
Composting is the process of bringing together plant or animal
wastes to hasten their decomposition. The result of this process
is a nutrient-rich organic fertilzier called compost or humus.
Farmers have practiced composting for thousands of years. They
knew that the use of plant and animal wastes would return nutrients
to their soil and enrich their farmlands. This in turn
promoted the growth of their crops. In sum, they took advantage
of all the plant and animal wastes that were so abundant and made
rich compost from them, instead of burning them or throwing them
Composting, however, is not to be regarded as a basis of
permanent soil fertility. This concept is inapplicable because
the application of decomposed waste will not neutralize excessive
soil acidity (i.e., increase soil pH) nor will it supply
corrective applications of nutrients such as phosphorus on a
phosphorus deficient soil.
The most attractive and feasible concept is the use of composting
in a gardern plot. The advantage is: the ease with which the
plant residues from the garden may be supplemented with those
grown elsewhere.
Adding compost to soils high in clay loosens and improves
compacted soil. This increases both the infiltration and water
holding capacity of the soil. In sandy soils, the addition of
composts increases the organic matter content of the soil, which
in turn increases the soil's ability to store water. By
increasing the infiltration of water into the soil, compost can
also help to reduce soil erosion. Compost contributes nutrients
from organic materials that would otherwise have been wasted.
This more favorable soil environment can increase the depth and
density of root growth. Composting also favors plant growth by
destroying many harmful weed seeds, insect eggs, and disease
organisms during a stage where a lot of heat is generated. Due to
the positive influence on chemical and physical properties of a
soil, compost can increase the productivity of your land.
Fine finished compost serves as an excellent soil basis to
transplant seedlings into. When mixed into the seed bed, compost
provides nutrients and an extra source of moisture for the
germinating seeds. Compost can be applied throughout the growing
season to crops as a sidedressing mixed in a depth of an inch or
so just before a rain. Mulching with compost nourishes the crop
while controlling weeds. In locations where plots of land are
not available, compost can serve as the soil base of potting soil
for indoor or container gardening. Composting is also an
excellent way to utilize fast growing plants such as water
hyacinths, which otherwise would create disposal problems.
Decomposition is part of nature's life cycle. Grasses, trees,
weeds, shrubs, and other succulent plants obtain carbon, hydrogen,
and oxygen from air and water and the dissolved nutrient
elements nitrogen, phosphorus, potassium, calcium, magnesium,
sulfur, boron, copper, iron, manganese, zinc, and molybdenum from
the soil. Then, through the green chlorophyll of their leaves
and with energy from the sun, they manufacture food products that
nourish other forms of life, including human beings.
At the conclusion of the growing season, leaves and other plant
parts wither, die, and become plant residue. However, the plant
residue (or animal residue) does not accumulate for long because
it is soon attacked by lower forms of plant and animal life. The
process of higher plant growth cannot go on indefinitely unless
nutrients such as nitrogen, phosphorus, potassium, sulfur, and
other elements are returned to the soil. Plant or animal wastes
contain compounds that must be broken down (decomposed) so the
nutrient elements contained in the waste can replenish the soil
and be reused for crop growth.
The replenishing process is carried out mostly by microorganisms,
including fungi, bacteria, algae, protozoa, nematodes, and worms.
Fungi and bacteria, of which there are several thousand species,
are responsible for most of the decomposing process. Some species
grow and decompose waste material under a fairly wide range of
environmental conditions, whereas others can perform only under
very specific conditions. As long as the environmental conditions
are favorable, microorganisms will quickly multiply to
decompose the waste material, no matter how much waste material
is available.
Good composting depends on a number of factors that influence the
activity of the microorganisms that cause decomposition. These
include: (1) the type of raw waste material to be decomposed;
(2) nutrient availability, especially nitrogen; (3) moisture;
(4) temperature; and (5) acidity (pH). Other factors to consider
in maintaining a composting pile are: nutrient losses during
composting, aeration, pests and diseases that may be transmitted,
the ratio of carbon to nitrogen, the presence of toxic substances
in the waste, etc. All of these factors are discussed in more
detail below.
Type of Raw Waste Material
Almost any plant or animal waste will decompose if preservative
measures have not been taken. And some wastes are more resistant
to decay than others and are not considered good compost
material. Food scraps, including meat scraps, can be used with
plant wastes. For rapid decomposition to form a good compost,
the waste must be high in carbohydrate, low in lignin compounds,
and have a nitrogen content about 1.5 percent or more.
Choose materials according to what is available to you. Here's a
list of good things to include (not in order of priority):
     *     rice husks
     *     coconut trash
     *     sugarcane waste
     *     leaves
     *     water hyacinth
     *     corn stalks and husks
     *     bean plants
     *     kitchen wastes
     *     spoiled food
     *     sawdust or wood shavings
     *     banana skins and leaves
     *     crushed animal bones
     *     seaweed
     *     garden trash (e.g., weeds, stalks, leaves, pads)
     *     manure from cattle, chicken, pigs, etc.
Many materials for composting can be obtained free from
manufacturers such as:
     *    dried blood, bones, and hair from animal slaughter
     *     hulls from graineries (rice, corn, cocoa, beans,
     *     coal ashes
     *     fish scraps from fisheries
     *     hair from barber shops
     *     molasses residue from sugar factories
     *     sawdust and woodchips from sawmills
     *     leather dust
Items that should not be composted include:
     *     plastic              *    glass bottles
     *     tin cans             *    wax coated cardboard
     *     stones               *    newspaper with colored ink
     *     human waste          *    waste from domestic cats
                                   and dogs
You should never use human waste in a compost which is to be
applied to an area where food crops are to be raised for either
humans or animals which will be used for meat. Depending on a
person's diet, living location, and health, the human waste can
contain metal and chemical compounds which could be hazardous.
By composting these compounds can accumulate to high levels
within soils. Some plants selectively take up thse compounds.
When eaten by humans they can pose a health risk. Thus, it is
best not to compost human waste unless a complete chemical
analysis can be performed to assure its safety.
Remember, animal waste products such as meat and fish scraps are
good too, but may attract hungry dogs, flies, and other insect
pests to your pile. One word of caution: manure piles are
notorious for attracting flies and other insect pests and the
same can happen in compost piles. For steps that can be taken to
prevent this from happening, see "Pests, Toxins, and Other Undesirables,"
page 10.
To speed up the decomposition process, you will want to break up,
chop, or grind large chunks (e.g., corn stalks, banana leaves) of
raw waste material into small, degradable pieces. Remember, the
finer the waste is shredded, ground, or pulped, the easier and
faster the decomposition will be.
Nutrient Availability and the Carbon-to-Nitrogen Ratio
Be sure the plant or animal waste to be decomposed contains a
sufficient amount of nitrogen. Waste that is deficient
particularly in nitrogen, or in other elements such as
phosphorus, potassium, calcium, magnesium, sulfur, boron, copper,
iron, manganese, zinc, and molybdenum, will slow the growth of
bacteria, making decomposition difficult.
Generally, plant wastes should contain about 1.5 percent or more
nitrogen for bacteria to function properly during the
decomposition process. For wastes high in carbohydrate and low
in protein, you may need to apply about 10 kg of nitrogen (25 kg
urea or 40 kg ammonium sulfate) per ton of waste.
Carbon-to-Nitrogen Ratio. Generally, the ideal carbon-to-nitrogen
ratio of a good compost pile is about 30:1. If the ratio is
either much higher or much lower than 30:1, the decomposition
process might slow down. Table 1 shows the carbon-to-nitrogen
ratios for a variety of raw waste materials. Of the material
listed in that table, those whose carbon-to-nitrogen ratios fall
in the mid range can be combined or used individually for
composting without upsetting the ratio. However, those materials
whose carbon-to-nitrogen ratios fall to either extreme of the mid
range will cause the ratio to be either too high or too low. So,
if you use a material that has a low carbon-to-nitrogen ratio,
you will also need to use a material whose carbon-to-nitrogen
ratio falls in the high range, enabling the two materials to
balance each other out.
           Table 1.  Carbon-to-Nitrogen Ratio and Nitrogen
                     Content of Compost Materials
                   Percentage of                        Percentage of
Raw Waste            Nitrogen      Carbon-to-Nitrogen      Moisture
Material            (Dry Basis)         Ratio           (Fresh Basis)
Fish scraps          6.5-10                4:1                 80
Poultry manure       6.3                   4:1                 75
Meat scraps          5.1                   6:1                 65
Fresh grass
clippings            4.0                  12:1                 95
Sun-dried grass
clippings            2.4                  19:1                 40
Raw garbage          2.15                 25:1                 90
Mixed fresh
garden debris        2.0                  20:1                 80
Cow manure           1.7                  27:1                 80
Seaweed              1.9                  19:1                 90
Fresh leaves         1.5                  30:1                 80
Oat straw            1.05                 48:1                 25
Dry leaves           1.0                  45:1                 40
Raw sawdust          0.25                208:1                  5
Determining the Carbon-to-Nitrogen Ratio of Your Compost. List
the various ingredients in your compost and the approximate
weight for each. Using the data from Table 2, list for each
ingredient the fresh weight, the percentage of moisture, the
percentage of nitrogen, and the carbon-to-nitrogen ratio. If the
specific material you are using does not appear on the table,
estimate the characteristics by comparing it to similar material.
             Table 2.  Determining the Carbon-to-Nitrogen
                       Ratio of Your Compost
                   Fresh                   Percentage of   Carbon-to-
Characteristic     Weight     Moisture        Nitrogen        Nitrogen
Ingredient        (Pounds)   (Percent)      (Dry Basis)        Ratio
Chicken manure       50          50               6.00           4:1
Sawdust              50           5               0.11         511:1
Food garbage         50          80               2.15          25:1
Dry leaves           75          25               1.00          45:1
Grass clippings      50          95               4.00          12:1
Total               275
Determine from the assembled data the following quantities for
each ingredient:
     *     the pounds dry weight by subtracting from the fresh
          weight the percentage of moisture;
     *     the pounds nitrogen by multiplying the dry weight by
          the percentage of nitrogen contained on a dry-weight
          basis; and
     *     the pounds of carbon by multiplying the pounds of
          nitrogen by the carbon-to-nitrogen ratio.
Compute for the total compost the cumulative moisture content by
dividing the total dry weight by the total fresh weight.
     Example:   144.5
               -----   =   53 percent
Compute for the total compost the cumulative carbon-to-nitrogen
ratio by dividing the total pounds of carbon by the total pounds
of nitrogen.
     Example:   62.80
               -----   =   27 percent
Balancing the Carbon-to-Nitrogen Ratio. Spreading a thin layer
of well-rotted manure within layers of fresh plant waste provides
a good source of nitrogen. Table 1 shows the percentage of
nitrogen and phosphate for several types of animal manure.
           Table 3.  Average Nutrient Content of Animal Manure
Type of          Amount of Nitrogen      Amount of Phosphate
Animal               (Percent)                (Percent)
Rabbit                       2.4                          1.5
Chicken                      1.1                          0.8
Sheep                        0.7                          0.3
Horse                        0.7                          0.3
Duck                         0.6                          1.4
Cow                          0.6                          0.2
Pig                          0.5                          0.3
Any mixed fertilizer containing nitrogen will be helpful if
applied at the rate of about 10 kg per ton of waste. The other
elements, including phosphorus and potassium, which might be in
the mixed fertilizers, will promote decomposition also, especially
if the waste being decomposed is low in these elements.
To increase the rate of decomposition, a compost pile should
always be moist but never too wet. Bacteria will grow under a
wide range of moisture conditions--from almost dry to saturation.
However, the best moisture for aerobic decomposition will be less
than saturation but about that of green plants. In soils, it
will be slightly above the field capacity or the amount of water
a soil retains against gravity. There will be a marked reduction
in the number of bacteria and fungus with drying and a great
reduction in the rate of decomposition. So the residue should be
kept moist but not saturated.
In tropical areas it may be necessary to cover the compost pile
with removable mats or temporary shelter to keep rains from
saturating the pile.
Bacteria grow and decompose wastes at a rather wide range of
temperatures, but for composts the optimum temperature is around
30[degrees] to 37[degrees] C, especially during the initial stages of the
decomposition process. Turning the pile to permit air to get in
will cool the mass. The temperature can also be moderated by
wetting the compost pile. If the temperature is kept low, say
below 20[degrees]C, the rate of decomposition will slow down.
One note of caution: the process of decomposition generates
heat, and if fresh plant wastes are packed tightly in a pile with
adequate moisture, the pile may become quite hot. Many barns
have burned down because uncured hay stored in them began to
decompose and generated enough heat to start a fire. This is
known as spontaneous combustion. The appearance of ash spots in
the compost indicates that temperatures are too high and steps
should be taken to cool the pile.
Acidity (pH)
Like other conditions, acidity greatly influences the type and
number of microorganisms required for decomposition. Some
different species of microorganisms will grow at various acidity
levels--from very acid (pH 1.0) to strongly alkaline (pH 11.0).
Plant wastes decompose best in the pH range of 6.0 to 7.5.
You may need to add some finely ground limestone (preferably
dolomitic lime) to keep your compost pile from becoming too acid.
Usually 25 kg to 50 kg of limestone per ton of waste sprinkled
through the pile is enough to do the job.
Nutrient Losses
Some valuable nutrients, particularly nitrogen, can escape during
the decomposition process. For example, one of the end products
of decomposition is ammonia, which can convert to a gas and
evaporate into the atmosphere, unless you mix fine-soil clay or
ground phosphate into your compost pile. In addition, nitrate,
ammonia, and potassium ions can seep through the soil, enter the
ground water, and dissolve if too much water is applied. And in
poorly aerated pockets of the waste undergoing decomposition,
valuable nitrogen gas can evaporate into the atmosphere.
You can avoid the loss of nutrients by:
     *     placing a fence (woven wire) or wooden slats on all
          four sides to maintain the shape of your pile and to
           keep animals out;
     *     not overwatering your pile; and
     *     mixing fine soil clay or ground phosphate into your
A thin layer of soil on the surface of your pile is good. This
absorbs ammonium ions and prevents the loss of nitrogen. The soil
layer also discourages insect pests from breeding in your compost
If your compost pile (or soil) is well aerated, the
microorganisms can obtain oxygen from the atmosphere, and
decomposition will be aerobic, with aerobic bacteria and fungi
predominating. If your compost pile is compacted, saturated with
water, and poorly aerated, the anaerobic bacteria will take over.
Turning the contents of your compost pile at least once a week
will: (1) prevent the pile from getting waterlogged; (2) aerate
the contents, which promotes rapid decomposition of the raw waste
material; (3) mix and spread the nutrients uniformly throughout
the pile; and (4) keep the pile from smelling bad.
You can test whether your pile needs to be turned by inserting a
stick into the center, and removing the stick after a few
minutes. If the stick smells bad, turn the pile. If the pile is
dry, add enough water to moisten it.
Clearly, if you turn the contents of your compost pile more
frequently, you will produce compost in a shorter period of time,
given that all other factors are present. In temperate regions,
if you do not stir the pile at all, it will take about four to
six months to produce compost. If you turn the pile once or
twice every other month, it will take about two to three months
to produce compost. If you turn it once every other day (i.e.?
four or five times in two weeks), your compost will be ready in
about two weeks. In tropical regions these time periods will
likely decrease.
Pests, Toxins, and Other Undesirables
A major problem in using composts is the possibility of spreading
disease organisms (fungi and virus) and insects. Spores from
disease pathogens may carry over in the compost pile and then be
spread over a field to a new crop. Though heat produced in the
compost pile during decomposition may destroy weed seeds and most
insects, the spores of many fungi, including the fungi causing
some plant diseases, may not be destroyed. For this reason,
tobacco, potato, and tomato crop wastes are not recommended for
use in compost piles as they may carry serious plant diseases.
To protect a compost pile against insect pests, spread a thin
layer of soil over the top of the pile. This soil layer also
prevents the loss of nitrogen.
Do not add any raw waste materials to your compost pile that have
been treated with herbicides, insecticides, feed additives, or
medications (e.g., antibiotics used in animal feeds or injected
into animals). Such materials risk (1) slowing down the decomposition
process; (2) retaining nondegradable amounts of toxins
in your compost; (3) killing your food crops caused by toxins in
your compost.
Correcting Problems During Composting
If your compost pile does not heat up:
     *     You may not have used enough nitrogenous material.
          This means you may have used too much sawdust, paper,
          or straw, all of which have very high carbon-to-nitrogen
          ratios due to their high cellulose and lignin
          content. To correct this problem, simply add more of a
          good nitrogen source to your compost pile.
     *     Or you may have added too much water to your compost
          pile. Too much water suffocates the aerobic organisms
          (i.e., they need oxygen to function) to the point where
          the anaerobic organisms (i.e., they work in an oxygen-free
          environment) take over, producing ammonia and bad
          smells. To correct this problem, turn your compost
          pile frequently or layer the raw waste material into a
          long-term compost pile.
If your compost pile gives off a strong smell of ammonia:
     *     You may have added too much of a high nitrogen source
          to your compost pile. To correct this problem, simply
          add old leaves, straw, or shredded paper in small
     *     Or you may have added too much limestone or other
          element high in calcium carbonate to your compost pile.
          This is difficult to remedy, but adding acid leaf
          litter and wet garbage may help. Next time, add the
          calcium to the soil rather than to the compost pile.
Recognizing Finished and Semi-Finished Compost
The following are signs of finished compost:
     *     ammonia smell is gone;
      *    the temperature of the compost pile has cooled down
     *     the compost is crumbly, dark, and sweet smelling; and
     *     at least three species of arthropods are present (e.g.,
          the sow and pill bug, ground beetle, and centipede).
Indications of semi-finished compost that can best finish
composting in soil are:
     *     the compost pile smells slightly of ammonia;
     *     the temperature has started to decline but steam still
          comes off; and
     *     possibly one or two species of arthropods are present.
When and How to Apply the Finished Compost
It is best to use the compost when it is still fresh. Remove the
compost in sections from top to bottom of the pile rather than
from the top only. If time and labor permits screen the compost
through a 0.6 cm mesh screen and return the larger materials to
the compost pile. To avoid losing the compost to wind or water
erosion it is best to incorporate it into the soil, particularly
when it is used in large or sloping land areas.
A wide range of composting methods is available. These extend
from simply adding raw waste material to soils and allowing it to
decompose under natural conditions, to sophisticated containers
with special chemical fertilizers that help raw waste material to
rot quickly. Because chemical fertilizers are costly and not
always readily available to people in developing countries, we
have focused only on those composting methods that do not
require commercial fertilizers.
As you familiarize yourself with the various composting methods
outlined in this section, keep in mind that you may have to adapt
specific methods to local conditions and available resources.
You can modify a particular method a little to fit your resources
without decreasing its overall effectiveness.
The size of a compost pile depends upon the amount of raw waste
material available and how it is to be used. The biggest factor
is to have a manageable pile large enough to take care of
available waste materials but small enough to be tended easily.
If great quantities of material are available, such as from a
slaughter house or sugar factory, several smaller piles will
probably be more manageable than a single large one.
Composting in Pits or Heaps
Although natural composting (i.e., decomposing raw waste material
directly in the soil) retains just as many nutrients as does
controlled composting (composting in a pile), the latter method
nevertheless offers more:
     *     raw waste material decomposes much faster in a pile;
     *     the temperature within a compost pile is much higher
          than that found in soil;
     *     controlled composting kills many weed seed and reduces
          potential pathogens;
    *    decomposed compost applied to soil loosens hard,
        compacted soil immediately, allowing the soil to take
        up oxygen and to absorb water in a much shorter period
        of time; and
    *    adding decomposed manure to soil promotes the growth of
        food crops, whereas adding fresh, undecomposed manure
        can damage the crops (i.e., the crops burn due to the
        high amount of nitrogen in fresh manure).
Choose a protected area, well drained and close to a water
source. The site should also be conveniently located since it
should be checked regularly. In temperate climates it may be
best to avoid shaded areas since this will lower the temperature
during cool seasons. In tropical or arid regions, shade may be
more beneficial in decreasing moisture lost by evaporation.
Chop or crunch under a roller all hard materials such as sugarcane
stubbles and dry stalks. Split up and cut all the soft but
bigger-sized materials like banana stumps. Dig a pit approximately
1.5m x 1.5m x .5m deep. Heap all the available refuse
around the pit. To make the material decompose easily, use a
"starter." The starter can be dung or urine. If these are not
available, well-decomposed manure, tank silt, or surface scraping
from forests can be used. To make a good compost, you also need
some ash and dry earth.
As shown in Figure 1, organic materials are layered in categories

uc1x14.gif (437x437)

in the compost pile and kept moist. To prepare the compost pile,
put the refuse in the pit in a layer about a foot high. Sprinkle
16 gallons (four or five buckets) of water and a thick paste made
with 60 pounds (two buckets) of dung in 16 gallons of water.
Spread half a basket of ash and one basket of the starter on the
layer. Put the second layer of trash over this. Five such
layers will bring the heap two feet above the ground level.
Cover this with a three-inch layer of soil on the top. See to it
that you fill the pit completely in a day or two.
Speed Composting
Speed composting requires that all materials either be chopped
into small particles (large kitchen scraps, weeds, straw) or
already come in small sizes (grass, leaves) and that the slower
decaying materials such as wood, twigs, eggshells and bones not
be used.
The volume of the compost pile should be no less than one cubic
meter to allow the generation and retention of heat. Ingredients
must be layered by categories (dry, green and manure) so that the
pile builder can estimate the ratio of the different materials.
Essential to the speed composting method are:
    *    frequent turning,
    *    proper moisture levels, and
    *    sufficient amounts of nitrogen to promote decomposition.
Here is a simple formula for speed composting:
    *    Loosen the soil in the area where the pile is to be
    *    Build a bin no smaller than 1m x 1m x 1m.
    *    Layer compost ingredients as follows:
        - Bottom layer--approximately 6 inches of absorbent
        material (straw or sawdust).
        - 4 inches of green garden and kitchen wastes.
        - 2 inches of manure, possibly mixed with soil.
        - 3 to 6 inches dry roughage (dry grass, leaves, or
    *    Repeat this layering until the bin is full, sprinkling
        the layers with water as you go.
    *    Every second or third day, turn the pile with a
        pitchfork or shovel. Turn the outer layers inward,
        mixing thoroughly from top to bottom. Turning the
        pile every day speeds up the decomposition process.
    *    Keep the pile moist but not waterlogged.
    *    Compost should be ready to spread over your farmland in
        about one month.
The resources, materials, and equipment necessary for composting
depend on what composting method you employ. Nevertheless, for
basic composting you need:
    *    plant residues and/or animal wastes;
    *    something with which to turn the compost material
        (e.g., a shovel, pitchfork);
    *    a sufficient supply of water to keep the compost
    *    a cutting tool, (e.g., a machete) to break up large
        chunks of raw waste material;
    *    a fence of woven wire, wooden slats, or bamboo, or a
        simple pit to maintain the shape of the compost pile;
    *    a supply of urea or ammonium sulfate in case you use
        raw waste material that is low in nitrogen;
    *    a supply of finely ground limestone to maintain the
        acidity level of the compost pile;
    *    a supply of clay loam, fine soil clay, or ground
        phosphate to prevent the compost material from losing
        valuable nutrients during and after the decomposition
        process; and
    *    some woven mats, a thick layer of straw, or a straw
        root to protect the compost pile when it rains.
There are essentially four steps in the controlled composting
process that require energy use: collecting the raw waste
material, preparing the compost pile, maintaining the pile, and
adding the finished compost to the soil. The quantity of energy
used in each of these steps depends primarily on the amount of
compost being produced. Compared to natural composting, which is
simply adding raw material to the soil and letting it decompose
naturally, controlled composting in a pit or heap clearly requires
more energy. However, because controlled composting
speeds up the decomposition process, it can produce compost in a
shorter period of time given the right conditions.
The cost of composting depends on the amount of raw material
available, and whether people and equipment must be hired to
collect and process it and return the compost to the soil. Costs
must be balanced against the benefits of increased soil
fertility, crop production, etc.
The amount of labor needed depends on the method used, size of
compost pile, and availability of materials. For a household
compost pile, one person may spend on average between one and
three hours a week maintaining a pile. This time commitment will
vary each week depending on the stage of decomposition of the
Composting is typically done on a small-scale basis within
households or on small farms. However, where there is an
abundance of raw materials and potential for marketing exists,
composting has been an economically feasible business.
Depending on the quantity and type of materials used, composting
has the potential to be sold as a soil conditioner or as an
organic fertilizer. This market tends to increase near urban
areas where small-scale gardening requires a source of soil. If
raw materials are readily available and labor or low cost
equipment are available, composting has the potential to be
maintained as a business.
Due to the potential health problems there may be laws in more
populated urban areas which prohibit the use of certain materials
for composting. These restrictions should be explored.
The main disadvantage of composting is that it can be time
consuming and the pile must be checked regularly. Beyond this the
disadvantages of composting only become apparent when proper care
for the compost pile is not followed. Insects and animals can be
attracted to the pile if the raw materials are not selected or
covered carefully. Disease and weed problems can increase if the
compost pile did not heat up sufficiently (to kill them while
composting). The pile can be a potential fire hazard if
moisture, temperature, and aeration are not watched regularly.
Composting is relatively inexpensive and simple. Thus, if you
want to convert waste organic materials to fertilizer, composting
would be a good choice.
On the other hand, if large quantities of raw materials are
available and you want to produce more than just fertilizer, you
might consider biogasification as an alternative. With biogasification,
raw waste materials can be digested under specific
anaerobic conditions, and returned to the environment in the form
of fertilizer and fuel, without degrading the environment. Biogasification
requires a considerably larger investment in capital,
materials, and labor. For example, the equipment (i.e., a
biogas digester, systems, pumps) necessary for biogasification is
generally more expensive than the equipment necessary for
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