SIMULATION OF DURUM-WHEAT (TRITICUM-TURGIDUM SSP DURUM) GROWTH UNDER DIFFERENT WATER AND NITROGEN REGIMES IN A MEDITERRANEAN ENVIRONMENT USING CROPSYST

CropSyst, a cropping system simulation model, was evaluated for its ab ility to simulate growth, yield, and water and nitrogen use of two whe at cultivars (Cham I and Hourani). These cultivars were grown under di fferent water (rainfed, 60% and 100% of crop water requirements) and n itrogen (without and with 100 kg N/ha) regimes in a Mediterranean type of environment at the Tel Hadya Research Station of ICARDA. Data from three contrasting growing seasons (1989/90 to 1991/1992) were used in these simulations. Soil characteristics, initial conditions of availa ble moisture, N and organic matter, and daily weather data were input to CropSyst. Crop input parameters were mostly selected from the model documentation or determined from the experimental data. A few cultiva r-specific parameters were adjusted within a narrow range of typical f luctuation by model calibration. Results showed that CropSyst was gene rally able to simulate evapotranspiration, crop N content, green leaf area, aboveground biomass, and grain yield as observed in the field ex periments. Overall, the magnitude of the root mean square errors,vas a bout 10% of the observed means with two exceptions (25% and 32%). Inde x of agreement between predicted and observed values fluctuated from 0 .90 to 0.98 (a value of 1.0 indicating excellent agreement), with most values equal or better than 0.95. Copyright (C) 1996 Elsevier Science Ltd