Onion is crucial vegetable crop, but its traditional methods of water application for crop production are strongly intensive in water scarcity region. The application of pulse drip irrigation (a relatively modern technique) adds practical value for water-scarce regions. This study evaluated the performance of the AquaCrop model, a physically based and water-driven crop model, for simulating growth, yield, evapotranspiration, and water productivity of white onion (Allium cepa L.) under pulse drip irrigation in the sub-humid region of Konkan, Maharashtra, India. A two-year field experiment (2015–2016) was conducted using three irrigation levels based on crop evapotranspiration (ETc) [I1 = 0.8 ETc, I2 = 1.0 ETc, and I3 = 1.2 ETc] in combination with four pulse irrigation strategies [P1 = continuous irrigation, P2 = two pulses, P3 = three pulses, and P4 = four pulses], arranged in a strip-plot design. The AquaCrop model was calibrated using data from 2015 and validated with independent data from 2016. Model performance was assessed using statistical indicators including coefficient of determination (R²), root mean square error (RMSE), model efficiency (EF), and Willmott’s index of agreement (d). The model demonstrated strong predictive capability for onion yield, biomass, evapotranspiration, and water productivity, with high agreement between observed and simulated values (R² ≥ 0.96, EF > 0.94, d ≈ 0.99). Yield and biomass were simulated with low RMSE values ranging from 0.68 to 1.31 t ha⁻¹ and 2.07–2.23 t ha⁻¹, respectively. Optimized pulse irrigation regimes, particularly P₃ and P₄, improved crop performance across irrigation levels. Deficit irrigation at 0.8 ETc achieved approximately 20% irrigation water savings compared to full irrigation, with yield reductions varying from 8.8 to 30% depending on pulse management. The results revealed that I2P₄ treatment estimated higher yield and which is at par with I3P₄, and significantly lower in I₁P₄ indicating a yield stability and water conservation under limited water availability. Cost analysis results indicate that highest gross monetary returns and benefit cost ratio was estimated for I2P4 (€9120.7 and 2.7:1) treatment combinations followed by I3P4 (€8836.4 and 2.6:1) treatment combinations, respectively. Overall, the study confirms the robustness of AquaCrop for simulating onion productivity and highlights pulse drip irrigation combined with optimized ETc-based scheduling as a climate-resilient strategy for enhancing water productivity in sub-humid and water-scarce regions.

Performance evaluation of AquaCrop model for onion (Allium Cepa L.) crop under different irrigation scenario in sub-humid region

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发表日期：

2026年7月9日

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Dnyaneshwar Arjun Madane,
Mahanand Mane,
Vikas Sharma

摘要

Onion is crucial vegetable crop, but its traditional methods of water application for crop production are strongly intensive in water scarcity region. The application of pulse drip irrigation (a relatively modern technique) adds practical value for water-scarce regions. This study evaluated the performance of the AquaCrop model, a physically based and water-driven crop model, for simulating growth, yield, evapotranspiration, and water productivity of white onion (Allium cepa L.) under pulse drip irrigation in the sub-humid region of Konkan, Maharashtra, India. A two-year field experiment (2015–2016) was conducted using three irrigation levels based on crop evapotranspiration (ETc) [I₁ = 0.8 ETc, I₂ = 1.0 ETc, and I₃ = 1.2 ETc] in combination with four pulse irrigation strategies [P₁ = continuous irrigation, P₂ = two pulses, P₃ = three pulses, and P₄ = four pulses], arranged in a strip-plot design. The AquaCrop model was calibrated using data from 2015 and validated with independent data from 2016. Model performance was assessed using statistical indicators including coefficient of determination (R²), root mean square error (RMSE), model efficiency (EF), and Willmott’s index of agreement (d). The model demonstrated strong predictive capability for onion yield, biomass, evapotranspiration, and water productivity, with high agreement between observed and simulated values (R² ≥ 0.96, EF > 0.94, d ≈ 0.99). Yield and biomass were simulated with low RMSE values ranging from 0.68 to 1.31 t ha⁻¹ and 2.07–2.23 t ha⁻¹, respectively. Optimized pulse irrigation regimes, particularly P₃ and P₄, improved crop performance across irrigation levels. Deficit irrigation at 0.8 ETc achieved approximately 20% irrigation water savings compared to full irrigation, with yield reductions varying from 8.8 to 30% depending on pulse management. The results revealed that I₂P₄ treatment estimated higher yield and which is at par with I₃P₄, and significantly lower in I₁P₄ indicating a yield stability and water conservation under limited water availability. Cost analysis results indicate that highest gross monetary returns and benefit cost ratio was estimated for I₂P₄ (€9120.7 and 2.7:1) treatment combinations followed by I₃P₄ (€8836.4 and 2.6:1) treatment combinations, respectively. Overall, the study confirms the robustness of AquaCrop for simulating onion productivity and highlights pulse drip irrigation combined with optimized ET_c-based scheduling as a climate-resilient strategy for enhancing water productivity in sub-humid and water-scarce regions.