Compton, J.A.F., Wright, M., Gay, C. and Stabrawa, A. (1992) A rapid method for loss assessment in stored maize and dried cassava. Interim report for project R5103. [Working Paper]

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Abstract

This paper describes a new method for the rapid assessment of losses in stored maize cobs and dried cassava chips (cossettes): the use of visual damage scales. The scales can be calibrated against conventional weight loss assessment techniques to permit the estimation of percentage weight losses in stores. The scales were first developed for a survey of Larger Grain Borer beetle (Prostephanus truncatus (Horn)) damage in farm stores in central Togo. They were constructed by sorting infested maize and cassava by eye into different damage classes(four classes for maize cobs and five for cassava chips). In the survey, each sampled cob or chip was scored for damage on the appropriate visual scale, using reference photos to ensure consistency. Advantages of the method include: it is quick and easy to use, increasing the number of stores which can be sampled; data loss or fabrication is reduced; anomalous results can be checked on the spot; and it increases farmer participation in the survey work. Methods of data analysis are discussed in detail. The raw (ranked) data can be analysed by chi-square tests, rank correlation and ordinal logistic regression. Alternatively, if the scales are used to estimate weight losses, this permits the use of more powerful techniques such as analysis of variance. The scales have potential for many types of survey work, especially rapid appraisal. one of the most interesting applications could be to estimate parameters such as loss in market value and loss of final food product (rather than whole grain), but more work is needed to devise appropriate ways of calibrating the scales for this purpose.

Item Type:	Working Paper
Uncontrolled Keywords:	loss assessment, maize, maize storage, cassava, dried cassava, post harvest loss, rapid assessment, assessment method, on-farm storage, Togo
Subjects:	S Agriculture > S Agriculture (General) S Agriculture > SB Plant culture
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science > Natural Resources Institute Faculty of Engineering & Science > Natural Resources Institute > Food & Markets Department
Related URLs:	Organisation
Last Modified:	27 Nov 2019 15:40
URI:	http://gala.gre.ac.uk/id/eprint/10762

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