ELSEVIEK Agricultural Systems, 51 (1996) 147-163 Copyright 0 1996 Elsevier Science Limited Printed in Great Britain. All rights reserved 0308-521X/96/$15.00 + .OO 0308-521X(95)00043-7 Simulation of Durum Wheat (Triticum turgirtum ssp. Durum) Growth under Different Water and Nitrogen Regimes in a Mediterranean Environment using CropSyst M. Pala International Center for Agricultural Research in the Dry Areas (ICARDA), P. 0. Box 5466, Aleppo, Syria C. 0. Stockle Biological Systems Engineering Dept., Washington State University, Pullman, WA 99164- 6120, USA H. C. Harris International Center for Agricultural Research in the Dry Areas (ICARDA), P. 0. Box 5466, Aleppo, Syria (Received 27 September 1994; revised version received 20 June 1995; accepted 28 June 1995) ABSTRACT CropSyst, a cropping system simulation model, was evaluatedfor its ability to simulate growth, yield, and water and nitrogen use of two wheat cultivars (Cham 1 and Hourani). These cultivars were grown under dtxerent water (rainfed, 60% and 100% of crop water requirements) and nitrogen (with- out and with 100 kg N/ha) regimes in a M editerranean type of environment at the Tel Hadya Research Station of ICARDA. Data from three con- trasting growing seasons (1989190 to 1991/1992) were used in these simu- lations. Soil characteristics, initial conditions of available 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 cultivar-spectjic parameters were adjusted within a narrow range of typical fluctuation by model cali- bration. Results showed that CropSyst was generally able to simulate 147