Application of EPIC model for irrigation scheduling of sunflower in Southern Italy

Abstract

A crop simulation model was used to optimize irrigation scheduling for sunflower grown in Southern Italy. The EPIC model, calibrated and validated in previous studies, was run for a 45-year simulation with climatic data measured daily, using 66 scenarios involving a combination of irrigation times (at five fixed data), seasonal irrigation amounts (from 0 to 200 mm) and irrigation frequency. The results obtained from the simulation indicate: (i) the superiority of single or double irrigation in the central phase (bud flower opening, flowering) for seed and biomass yield; (ii) the optimal value of seasonal irrigation water to be about 250–300 mm for the highest water use efficiency value; (iii) the highest profitability for the farmer achieved with a single irrigation of 200 mm at bud flower phase and a reduction of net income with irrigation at sowing or at seed ripening phases. The EPIC model, due to its sub-models (growth, weather, soil, management, water, erosion, economic, etc.), can be considered a useful tool for comparing several management strategies, and requires a minimum investment of time and money. This approach could be used at the farm level or on a larger scale.