A system has been developed to support agricultural policy formulation in Iran, which comprises three main components, i.e. resource analysis, policy impact assessment and policy evaluation.
The biophysical resource analysis was carried out using CGMS, the Crop Growth Monitoring System which includes a generic crop growth simulation model. This model simulates growth of annual crops in the potential and water-limited production situations, based on daily weather data, crop characteristics and soil physical characteristics. Results of biophysical resource analysis are used to determine biophysical input/outputs of crop production systems.
For policy impact assessment a distributed linear programming model was developed which simulates response of the various farm types to policy instruments. As reactions of farmers to policy instruments may be different, depending on their socio-economic situation and the biophysical characteristics of their land, a planning (modelling) unit was defined, homogenous in terms of biophysical and socio-economic characteristics. Developed model for planning units are aggregated to higher spatial scales considering various constraints in different spatial levels.
For policy evaluation, a multi-criteria evaluation model was developed and applied. In this model, policy analysis was carried out through overall assessment of the various economic, social and environmental indicators to evaluate the effectiveness of the policy instruments. In an experiment, the developed system was applied to assess the impacts of three policy instruments, aiming at increasing agricultural water productivity in Borkhar sub-district, Iran.