We tested the capability of CropSyst, a cropping system simulation model, to simulate cropping systems al two locations (Modena and Foggia) representative of the largest plain areas of Italy. Experimental data collected from rotation experiments during the period 1985-91 were used to calibrate and validate the model. The data set available was not detailed enough to test most of the sub-models, but it was adequate for a satisfactory test of overall model performance. Simulations were conducted for 6-year rotations providing initial conditions of the first year without reinitializing the model in later years in the rotation sequence. Model evaluation was performed with the understanding that a large amount of variability was present in the data and that rotation effects other than water (e.g., diseases) were not accounted for by the model. The phenology sub-model proved sufficiently accurate, showing some limitation only in the case of winter cereals. Model simulations of maize, soybean, and barley growth at Modena, and sorghum and sunflower growth at Foggia were reasonably accurate. CropSyst was able to predict neither the yields of soybean grown as a second crop, nor the durum wheat yield variability in the rotations at Foggia. Although CropSyst was able to simulate reasonably well a number of cropping systems, the development of a more detailed field data base is desirable for further evaluation and improvement of the model for Italian conditions. (C) 1997 Elsevier Science B.V.
