A DIAGNOSTIC METHOD FOR ASSESSING REGIONAL VARIATIONS IN CROP YIELD

The diagnosis of agronomic problems in cropping systems is often limit ed to surveys among farmers, in which they ave asked about the problem s they encounter. This paper describes an alternative method of diagno sis to understand the variations in crop yield on a regional scale. It is based on multi-annual on-farm surveys, where data are collected on the cropping system, environment and crop-yield build-up. The differe nt steps of the method: choice Of study area and of farmers' fields; c hoice of methods; design of further experiments; and diagnosis itself, plus the way they are linked to each other, are developed and discuss ed. (C) 1997 Published by Elsevier Science Ltd.