Applicability of the Afrcwheat2 Wheat Growth Simulation Model in Hungary

The aim of the present work was to determine the applicability of the AFRCWHEAT2 wheat growth model under Hungarian conditions. The Farquhar model, which, when properly calibrated, gives a satisfactory description of the net photosynthesis of Hungarian winter wheat varieties at various atmospheric CO2 concentrations, temperatures and light conditions, was incorporated into the model. Both the original AFRCWHEAT2 model and the modified AF2MOD model were tested on long-term yield and climatic data series from Győr-Moson-Sopron County. It was observed that the average yield over the period 1980-1990 was well simulated by both models, but the AF2MOD simulated the annual fluctuations much better: the determination coefficients describing the correlation between the actual wheat yield in Győr-Moson-Sopron county over the whole period and the values generated using the models were r2 = 0.32 for the AFRCWHEAT2 model and r2 = 0.86 for AF2MOD. A comparison of the results simulated using the AFRCWHEAT2 and AF2MOD models demonstrated that detailed physiological submodels are required for the mathematical description of plant growth if yields are to be accurately estimated and the effects of environmental changes adequately described. A good example of this is the description of the effect of atmospheric CO2 concentration on simulated yield figures, which depended on the climate of the given year in the AF2MOD model, but was described by a simple linear function in the AFRCWHEAT2 model.