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close this bookTraditional Storage of Yams and Cassave and its Improvement (GTZ)
View the document(introduction...)
View the documentPreface
View the document1 Introduction
View the document2 Socio-cultural aspects involved in the production of roots and tubers
View the document3 Basic comments on the storage properties of roots and tubers
close this folder4 Yams
View the document(introduction...)
View the document4.1 The environmental requirements of yams
View the document4.2 The yam tuber
View the document4.3 Farm-economic aspects of yam production
View the document4.4 Yam harvesting
close this folder4.5 Causes of storage losses for yams
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View the document4.5.1 Dormancy
View the document4.5.2 Transpiration
View the document4.5.3 Respiration
View the document4.5.4 Germination
View the document4.5.5 Rot due to mould and bacteriosis
View the document4.5.6 Nematodes
View the document4.5.7 Insects
View the document4.5.8 Mammals
close this folder4.6 Traditional storage systems for fresh yams
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View the document4.6.1 Leaving the yam tubers in the ridges after maturity
View the document4.6.2 Storing the yam tubers in trench silos
View the document4.6.3 Storage of yam tubers in heaps on the ground
View the document4.6.4 Storage of yam tubers in clamp silos
View the document4.6.5 Storage of yam tubers under a conical protective roof made of maize or millet stalks
View the document4.6.6 storage of yam tubers in mud huts
View the document4.6.7 The storage of yam tubers in the yam barn.
close this folder4.7 Measures to improve traditional yam storage
View the document(introduction...)
View the document4.7.1 Care in harvesting transport and storage
View the document4.7.2 Curing
View the document4.7.3 Influencing dormancy
View the document4.7.4 Influencing the storage climate
View the document4.7.5 control of rot
View the document4.7.6 Control of nematodes
View the document4.7.7 Control of insects damaging stored produce
View the document4.7.8 Measures for protection from mammals
View the document4.7.9 The improved traditional yam barn
close this folder5 Cassava
View the document(introduction...)
View the document5.1 The environmental requirements of cassava
View the document5.2 The cassava root
View the document5.3 Economic aspects of cassava production
View the document5.4 Causes of limitations to storage for fresh cassava roots
close this folder5.5 Ways of and limits to. storing fresh cassava roots
View the document(introduction...)
View the document5.5.1 Storing cassava roots in the soil after maturity
View the document5.5.2 Traditional methods of storing fresh cassava roots
View the document5.5.3 Storage of fresh cassava roots in clamp silos
View the document5.5.4 Storing fresh cassava roots in crates
View the document5.5.5 Storing fresh cassava roots in a dip
View the document5.5.6 Storing fresh cassava roots in plastic bags
View the document5.5.7 Use of modern methods to store fresh cassava roots
View the document5.5.8 Measures to prepare fresh cassava roots for storage
View the document5.5.9 Suitability of storage systems for fresh cassava roots on a small farmholder level
close this folder5.6 The processing of cassava roots
View the document5.6.1 The purpose of processing
View the document5.6.2 Hydrogen cyanide and its release
View the document5.6.3 The production of cassava chips
View the document6 Summary
View the document7 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.