I. A decision support system to improve planning and management in large irrigation schemes

This paper describes a decision support system (DSS) that was developed to improve planning and management for the large irrigation schemes in the Ale ntejo region of Portugal. The system was designed to help in the analysis a nd evaluation of the crops and crop systems that can potentially be cultiva ted, together with identification of limitations affecting crop selection a nd crop yields. It integrates socio-economic and biophysical data at the fi eld level to analyse the performance of an irrigation scheme in terms of th e adoption of irrigation by farmers and farmers' incomes. The final output is given in the form of specific actions and policies for the irrigated are as. The DSS was designed initially to be used in the Alqueva project, a lar ge irrigation scheme that is under construction in Alentejo. Nevertheless, the final framework is generic in nature, being suitable for planning and p olicy evaluation in other large irrigation schemes. (C) 2001 Elsevier Scien ce B.V. All rights reserved.