Using the AquaCrop model to simulate sesame performance in response to superabsorbent polymer and humic acid application under limited irrigation conditions.

Abstract

Quantification of the effects of water consumption technologies on sesame performance has not been evaluated by any model yet. Field experiments were conducted to assess the sesame (Sesamum indicum L.) response to limited irrigation in an arid region. Experimental factors were irrigation levels (deficit and full irrigation; DI, FI respectively), application of superabsorbent polymer (SAP) (80 kg ha-1), foliar application of humic acid (HA) (6 kg ha-1), and control which were arranged in the split strip plot design. Sensitivity analysis demonstrated the robustness of the AquaCrop model for simulation of soil water content, sesame canopy cover, and final production. Satisfactory results were obtained for the simulation of biomass (B) (R2 = 0.92, EF = 0.87) and seed yield (SY) (R2 = 0.88, EF = 0.85). NRMSE (%) values for the simulated B (7.3%) and SY (6.9%) along with other model evaluation statistics confirmed the potential of the model for the study application. Model accuracy in simulating water use efficiency (WUE) (R2 = 0.70) and harvest index (HI) (R2 = 0.61) was slightly lower than SY and B. Comparison of the measured and simulated B, HI and WUE obtained for DI+SAP treatments revealed that the application of SAP under DI condition was an efficient approach and a useful alternative to FI at water scarcity conditions. Slight differences between the measured and simulated values of SY, B, HI, and WUE under conditions of application of SAP and HA as eco-friendly inputs and the results' consistency with other studies indicate the benefits of these inputs in arid regions for enhancing the performance of sesame crop.