II. The use of the DSSIPM in the Alentejo region of southern Portugal

DSSIPM is a decision support system that was developed to improve planning and management in large irrigation schemes. Paper I provided a description of the system, including its structure, databases and procedures. Here, the application of DSSIPM to the Odivelas irrigation scheme is described, a case study in the Alentejo region of Portugal. The results obtained suggest that the introduction of irrigation is likely to increase crop diversity and the income of farmers. Analysis indicates that the performance of irrigated areas will be affected by such diverse factors as crop prices, subsidies, the availability of water, land taxes and the price of water, the existence of markets for non-traditional crops, the size of fields and the technological skills of farmers. The development priorities for improving the economic performance of agriculture in the Odivelas region were identified. They include developing marketing and processing facilities, reformulating water prices and land taxes, improving water distribution, developing extension services, providing irrigation equipment and farm machinery to rent, and modifying land tenancy legislation.