Simulating crop response to Nitrogen-deficiency stress using the critical Nitrogen concentration concept and the AquaCrop semi-quantitative approach

Abstract

Simulation models are effective tools for evaluation of alternative management options. These models have been applied to address the impact of diverse environmental and management conditions on crop production. Nitrogen (N) is considered as the major nutrient influencing crop quality and quantity. In greenhouse cultivation, where both crops quality and quantity are important, application of a mathematical model which integrates different crop growth processes, is crucial. AquaCrop model employs a semi-quantitative approach for estimation of crop biomass under N-deficiency conditions. In AquaCrop model, the effect of soil N fertility stress on biomass production is simulated indirectly based on stress coefficients. However, proper fertilizer management requires the knowledge of crop N demand during growth period to ensure maximum production. In this respect, a direct simulation approach based on the concept of critical N concentration was employed. Two experiments with different N application rates were conducted on basil grown under greenhouse conditions. The AquaCrop model was initially parameterized for basil and then calibrated under N stress conditions. Validation results indicated an acceptable accuracy (17.20 %< relative root mean square error (RRMSE) < 19.10%) for biomass simulation by application of semi-quantitative approach. In contrast, the direct simulation approach performed better than AquaCrop model by RRMSE ranging from 7.48% to 12.97%. Results demonstrated that the direct simulation approach by considering the crop N status during simulation period is capable of improving soil fertility management which can lead to improve human and environmental health.