Traditional storage of yams and cassava and its improvement

90 pages

Table of contents

JOCHEN KNOTH
Cover: photo K. Gaesing

Published in 1993 by:

GTZ-Postharvest Project
Pickhuben 4
D-20457 Hamburg

a project of technical assistance carried out by:

Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH
Postfach 5180
D-65726
Federal Republic of Germany

© 1993 GTZ

The copyright of this publication is vested in the “Deutsche Gesellschaft fuer Technische Zusammenarbeit (GTZ) GmbH”. Applications for permissions to reproduce this publication, in whole or in part, by any method or process, should be addressed, with a statement of purpose and extend of the reproduction desired, to GTZ - Stabsstelle 01, Postfach 5180, D-65726 Eschborn, Germany

Contents

Preface

1 Introduction

2 Socio-cultural aspects involved in the production of roots and tubers

3 Basic comments on the storage properties of roots and tubers

4 Yams

4.1 The environmental requirements of yams
4.2 The yam tuber
4.3 Farm-economic aspects of yam production
4.4 Yam harvesting
4.5 Causes of storage losses for yams

4.5.1 Dormancy
4.5.2 Transpiration
4.5.3 Respiration
4.5.4 Germination
4.5.5 Rot due to mould and bacteriosis
4.5.6 Nematodes
4.5.7 Insects
4.5.8 Mammals

4.6 Traditional storage systems for fresh yams

4.6.1 Leaving the yam tubers in the ridges after maturity
4.6.2 Storing the yam tubers in trench silos
4.6.3 Storage of yam tubers in heaps on the ground
4.6.4 Storage of yam tubers in clamp silos
4.6.5 Storage of yam tubers under a conical protective roof made of maize or millet stalks
4.6.6 storage of yam tubers in mud huts
4.6.7 The storage of yam tubers in the yam barn.

4.7 Measures to improve traditional yam storage

4.7.1 Care in harvesting transport and storage
4.7.2 Curing
4.7.3 Influencing dormancy
4.7.4 Influencing the storage climate
4.7.5 Control of rot
4.7.6 Control of nematodes
4.7.7 Control of insects damaging stored produce
4.7.8 Measures for protection from mammals
4.7.9 The improved traditional yam barn

5 Cassava

5.1 The environmental requirements of cassava
5.2 The cassava root
5.3 Economic aspects of cassava production
5.4 Causes of limitations to storage for fresh cassava roots
5.5 Ways of and limits to storing fresh cassava roots

5.5.1 Storing cassava roots in the soil after maturity
5.5.2 Traditional methods of storing fresh cassava roots
5.5.3 Storage of fresh cassava roots in clamp silos
5.5.4 Storing fresh cassava roots in crates
5.5.5 Storing fresh cassava roots in a dip
5.5.6 Storing fresh cassava roots in plastic bags
5.5.7 Use of modern methods to store fresh cassava roots
5.5.8 Measures to prepare fresh cassava roots for storage
5.5.9 Suitability of storage systems for fresh cassava roots on a small farmholder level

5.6 The processing of cassava roots

5.6.1 The purpose of processing
5.6.2 Hydrogen cyanide and its release
5.6.3 The production of cassava chips

6 Summary

7 Bibliography