Effect of cropping strategies on the irrigation water productivity of durum wheat.

The importance of irrigation for durum wheat is often questionable because of possible spring rainfalls in the south-east of France. The cropping strategies i.e. plant density (PD), sowing date and irrigation management were analysed for improving irrigation water productivity (IWP). An experiment was carried out to calibrate and validate the PILOTE model. An adaptation of the potential harvest index to PD was implemented in PILOTE. The latter satisfactorily simulates different model outputs with coefficients of efficiency greater than 0.97. The model was em ployed for simulating the impact of cropping strategies on IWP for a long climatic series. According to model simulations, the necessity of irrigation is questionable under our conditions. IWP was notably lower under high PD than under low PD for the same sowing date. Under low PD and without irrigation it would be possible to obtain yield similar to that obtained under high PD with irrigation.