Modelling irrigation scheduling to analyse water management at farm level, during water shortages.

摘要

The area under irrigated maize has significantly increased in the Charente river basin during the last 10 years. Maize water requirements are maximum in the summer, the period with low water flows and highest environmental vulnerability. Irrigationmanagement strategies at farm level during water shortages are discussed. A computer programme called IRMA is used to represent the farmer's decision making process. The model was calibrated and validated using information collected through a detailed monitoring of irrigation and farming practices of three representative farms during two irrigation seasons. The accuracy of the model was good; the difference between measured and simulated cumulative water volume used was slightly less than 8.5%. Analysisof daily simulated water demand shows that farmers have adopted different strategies to deal with water shortages, depending on the physical and socio-economic characteristics of their farms. The application presented in this paper stresses the potential of the proposed approach, if used on a larger farm sample, to compare the expected impact of different water management policies on water demand and irrigation practices at the farm level.