Agricultural water nonpoint pollution control under uncertainty and climate variability

The objective of this paper is to study the probabilistic cost-effectiveness of the farm management practices supported by the European Union for reducing nitrate pollution. Our method consists in using a bio-physical model to evaluate the environmental and economic impacts of various scenarios characterized by a set of farm practices. The cost-effectiveness of each scenario is calculated for a catchment area located in the northeast of France, for various climatic years and under different assumptions of crop prices. The results show that it is not realistic to obtain a rapid reduction of nitrate concentrations by implementing the scenarios tested. In the long run and irrespective of the economic context simulated, the optimum scenario in the case studied is one that combines integrated fertilization with the introduction of catch crops. Our findings thus highlight the effectiveness of catch crops that are able to reduce variability of nitrate concentration and thus significantly reduce the risk of exceeding environmental constraints. They therefore provide some recommendations for policy-makers.