Parameterizing Key Elements for Simulating Pearl Millet (Pennisetumglaucum L.) Productivity In Semi-Arid Environments: A Calibration and Validation Approach

Given the water scarcity and nutritional importance of millet in semi-arid Northeastern Nigeria, this study evaluated the AquaCrop model's performance using pearl millet in Maiduguri. Two-year field experiments under deficit irrigation provided data for model evaluation. A custom millet crop file was developed, calibrated with 2022/2023 data, and validated with 2021/2022 data. The model accurately predicted canopy cover and biomass production across growth stages during calibration and reliably simulated biomass yield (BMY) and grain yield (GY) during both calibration and validation. Validation statistics showed strong agreement between observed and simulated values (R² = 0.94 and 0.97, RMSE = 0.55 and 0.42 t/ha, NSE = 0.92 and 0.31, and d = 0.90 and 0.91 for BMY and GY, respectively). The model's robustness under varying water conditions suggests its suitability for water management and climate change studies in the region. Furthermore, incorporating millet into the model's built-in crop files would enhance user experience and facilitate future simulations. Keywords: AquaCrop model, Crop simulation, Deficit irrigation, Pearl millet, Semi-arid region