ASSESSING STRATEGIES FOR WHEAT CROPPING IN THE MONSOONAL CLIMATE OF THE PAMPAS USING THE CERES-WHEAT SIMULATION-MODEL

We evaluated a series of management strategies for rainfed wheat cropp ing in a monsoonal climate in the Pampas using the CERES-Wheat model w ith 24 years of daily weather records. These strategies included the c ombination of two cultivars of different maturity (intermediate and sh ort) and two sowing dates (early and late), in two different locations (Pergamino and Marcos Juarez). In addition, the impact of not control ling weeds during the fallow preceding each crop was assessed. Simulat ion experiments showed that without limitations of nitrogen, maximum y ields could be achieved by early sowing of the intermediate-cycle cult ivar. The highest yield achieved by this strategy was partially associ ated with greater water consumption during the crop cycle, However, in the lowest-yield years of both sites, but particularly in Marcos Juar ez, the intermediate cultivar sown early did not appear to be the best option. An analysis of stability of grain yield indicated that late s owing of the short-cycle cultivar was the most stable system. For weed y fallows, the yield of the short-cycle cultivar was more affected tha n the intermediate one, particularly in years of low yield.