Environmental Variability and Multiple Site-Multiple Season Trials

Abstract

The rainfed regions that ICARDA operates in are characterized by high levels of environmental variability. This variability is observed temporally and spatially in climatic conditions and also, spatially, in soils and other physical factors. Technologies developed by researchers must weather the impact of environmental variability. Otherwise, adverse environmental conditions can produce severe failures and irreparably damage chances of adoption by farmers. Consequently, it is necessary to observe and assess how technologies perform under different environmental conditions. This can be a time-consuming and expensive process. Here, an approach is proposed whereby information from multiple season-multiple site experiments can be used efficiently towards the objective of taking environmental variability into consideration. Results pertaining to drilled barley (c.v. Beecher) from the trials conducted by the Farming Systems Program, across the rainfall transect in Aleppo province, Syria between 1979 and 1983, are used to illustrate the approach. The indications are that (a) economically optimal fertilizer recommendation for average environmental conditions would pay off around 80% of the time, (b) environmental information production, and (c) increases in marginal rates of return would cause fairly rapid decreases in fertilizer use.