AquaCrop model calibration and validation for chickpea (Cicer arietinum) in Southern Africa.

Abstract

The study parameterised and validated performance of AquaCrop model, to simulate attainable yields for chickpea crop in response to the effects of planting date in the Northestern Region of South Africa. Model calibration data were obtained from two field experiments of contrasting water regime, planted in 2014 winter season at University of Venda, South Africa, whilst data for model validation was obtained from 2015 planting season from the same station. The model performance was satisfactory, with a good combination between the simulated and observed canopy cover (CC), Soil water content (SWC), biomass (B) and grain yield (Y). All the statistical indicators (R2, RMSE, and MAPE) used to compare field observed and model-predicted parameters, showed good performance. For example, the regression analysis of simulated and observed yield showed a good relationship with R2 values of 0.949, 0.928 and 0.990 for early, normal and late planting dates, respectively, whilst RMSE was 0.135, 0.143 and 0.031 for early, normal and late planting dates. Similarly, SWC had strong regression relationship (R2 = 0.982, 0.949, 0.954, respectively, and a RMSE of 0.226, 0.696 and 0.310, respectively, in early, normal and late planting date). The results indicate that the model could be used for evaluating the effects of different planting dates on chickpea yield.