Traditional Storage of Yams and Cassave and its Improvement (GTZ): 2 Socio-cultural aspects involved in the production of roots and tubers

Traditional Storage of Yams and Cassave and its Improvement (GTZ)

(introduction...)

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

(introduction...)

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

(introduction...)

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

(introduction...)

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

(introduction...)

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

(introduction...)

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

(introduction...)

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

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

Seen from the perspective of the history of mankind, the societies whose nutrition is based on the cultivation of roots and tubers are very old cultures The settlement areas for these societies originally comprised the whole of the tropical equatorial region.

During the course of history, almost all "root and tuber societies" have either been infiltrated by cereal cultivating societies or destroyed by their hegemonic strivings. More or less intact "root and tuber societies" have only been able to survive and retain their cultural heritage until today m West Africa (Yam Belt) and on some islands of Oceania (COURSEY, 1981).

This, however, does not mean that all other former "root and tuber societies" which have been modified by external influences, have lost their specific heritage. On the contrary in these societies, the customs and traditions showing the high cultural status of roots and tubers have survived.

Thus the vegetation cycle (planting, harvesting and storing) is frequently embedded in a series of rituals serving to protect the roots and tubers The harvest of roots and tubers is tabooed until certain rituals supported by religious sanctions have been carried out.

In these societies, the individual plant often has a greater significance than the crop population. For yams for example, ridge beds and staking systems are set up for each individual plant it is the aim to maximise the yield for each plant (largest possible tubers) and not to maximise the area output. This concentration on the individual plant is also illustrated harvest technology: with the greatest care, only a definite number of tubers is harvested from each plant allowing it to continue to grow.

Post-harvest technology is also in line with the desire for harmony in these societies. The purpose of this is more to avoid longer periods of storage than to develop improved storage systems (LANCASTER and COURSEY, 1984). This may be one reason why traditional storage systems have a very simple concept and often show no signs of endogenous development. The traditional store for yams (yam barn) in West Africa does not only serve to preserve the tubers. It also has a symbolic character and is a sign of the economic prosperity and of the social influence of its owner

The overall field of post-harvest activities in these societies is often seen as an extension of household activities. It is therefore not surprising that the post-harvest tasks are the responsibility of the woman (LANCASTER and COURSEY, 1984) Gender-specific division of labour however, shows some differences depending on the variety of crop. The woman is thus involved in cultivating and storing cocoyams and cassava or even in charge of this. In contrast, the cultivation and storage of yams is exclusively a matter for men

Gender-specific division of labour is not exclusively based on traditional behaviour patterns Changes in socio economic conditions, e.g. temporary migration for reasons of employment, also affect labour division and cause changes in role allocation between man and woman.