Adaptation and use of a fuzzy expert system to assess the environmental effect of pesticides applied to field crops

Centre d'Etude pour un Developpement Agricole Plus Autonome (CEDAPA) is a group of farmers in Brittany (western France) which proposes a mainly pasture-based milli and meat production system defined by a set of prohibitions and obligations, CEDAPA farmers claim that their production system causes less environmental damage than the current systems used by most other farmers. With respect to pesticide effects this claim was examined by using an expert system (Ipest), which reflects the authors' perception of the potential environmental effect of the application of a pesticide to a field crop. Ipest requires three types of input variables: pesticide properties, site-specific conditions and characteristics of the pesticide application. It yields four output variables: one reflecting the rate of application of the pesticide, the other three reflecting the risk for three major environmental compartments (groundwater, surface water and air). In order to fit the hydrogeological conditions of Brittany and to decrease dependence on expert judgement, the Ipest system was modified and enhanced. An existing method for the estimation of runoff risk from the field was included. This new version of the expert system, Ipest-B, was used to compare the environmental effect of pesticide use on winter wheat, silage maize and fodder beet, which overall was largely similar. However, within each of the three crops, large differences occurred from pesticide characteristics, number of treatments and environmental conditions. This type of analysis helps to identify and recommend the least harmful treatment programmes for each crop. The Ipest system was shown to be flexible, and adaptable to the particularities of Brittany. An adaptation of the system to other regional conditions should be possible. (C) 2000 Elsevier Science B.V. All rights reserved.