Predicting biomass and yield of sweet pepper grown with and without plastic film mulching under different water supply and weather conditions

The model was calibrated using data from the F-treatment in 2012 at Stara Pazova and F*-treatment in 2011 at Sombor, given that the highest yields were recorded in these two cases. The difference between the measured and simulated values was 2.9% and 7.5% for yield and 7.6% and −14.3% for biomass, in Stara Pazova and Sombor, respectively. The calibration results showed a very good agreement between the measured and simulated values. The deviation of simulated yields from the measured values in the validation data set depended on weather and soil conditions. Namely, the match was very good in the case of well-watered pepper grown without plastic film mulching in the average year at Sombor (1.2%), and was the worst in the extremely warm year (−45.2%). Similar differences were noted in biomass. Based on statistical indicators, the coefficient of determination (R2) of pepper yield at Stara Pazova and Sombor was 0.61 and 1.00 and the Willmott index of agreement (d), 0.79 and 0.89, respectively. Thus the AquaCrop model simulates the yield of pepper grown with and without plastic film mulching quite well. Biomass simulations resulted in slightly lower values of R2 and d. The AquaCrop model can also predict the amount of water needed for pepper grown with and without black plastic mulch.