A practical assessment of food losses sustained during storage by smallholder farmers in the Shire Valley Agricultural Development Project Area of Malawi 1978/79 (G154)

摘要

An assessment of losses caused by insects and sustained by farmers who stored maize or sorghum on their farms was undertaken in the Shire Valley Agricultural Development Project area in Southern Malawi. During the survey current recommended methodology for undertaking loss surveys and for sample analysis was critically evaluated under practical conditions. Probability procedures and stratified, random sampling methods were used to choose the farmers who participated in the exercise. Each farmer was visited as soon after harvest as possible so that the amount of produce stored could be ascertained. Thereafter, at approximately monthly intervals local extension workers collected samples of produce for analysis and information regarding food consumption patterns from each farmer. At each visit the extension worker had to complete a questionnaire. Some of the questions were found to be too complex for the field worker, though in general the information retrieved provided useful data. Samples of grain were analysed for losses by determining the weight of a standard volume of grain (SVW) and comparing the extrapolated dry weight to that of a known sample. A second method, that of counting and weighing damaged and undamaged grains was also employed. Difficulties were experienced with both methods because of the relatively large variations in the results obtained and because of the low levels of loss. Significantly greater losses were recorded by the SVW method than by the count and weigh method. Most farmers did not store their produce beyond the dry season when insect activity was low. The lack of insects was reflected in the low losses obtained, 1 - 2% for sorghum and 2- 5% for maize. However, even those few farmers who stored through the rains did not lose a significantly greater percentage.