Analysis of policy instruments for control of nitrate pollution in irrigated agriculture in Castilla y León, Spain

Irrigated agriculture is one of the most important sources of nitrate pollution of water resources. For this reason, during the past decade, various policies have been proposed in order to prevent this negative impact of farming activities. The aim of this work is therefore to analyze the effects of the joint application of the last Common Agriculture Policy (CAP) reform with different policy instruments designed to mitigate nitrate pollution. To this end, models based on Positive Mathematical Programming have been developed to enable simulating irrigators' productive behaviour in the event of the implementation of these instruments. The results indicate that the latest CAP reform (partial decoupling of subsidies) will by itself lead to an important reduction in nitrate pollution. If this reduction is not regarded as being sufficient, other specific policy instruments could further reduce this source of pollution. In this sense, the most suitable one could be the application of nitrogen fertilization quotas.