FAO AquaCrop Model Performance: in Green Canopy Cover, Soil Moisture and Production of Maize at Middle and Lower Reaches Plain of Yangtze River of China

Abstract

Crop water productivity models are valuable tools for investigate the crop responses to the water-management strategies and ameliorate the efficiency of water use in agriculture. The objective of this study was to evaluate the performance of AquaCrop model for maize crop (Zea mays L.) under full, excessive and deficit applications of drip irrigation in semi-humid region of China. The evaluation results emphasized the model accuracy in simulations CC, SWC, B*, Y and WUE with satisfactory performance in full irrigation, and moderate water stressed treatment T2 of 75% of full irrigation. This accuracy declines in circumstances of excessive irrigation T1 of 125% of full irrigation, and high water stressed T3 of 50% of full irrigation. The RMSEs and NRMSEs in simulated CC, and SWC for full irrigation, T1, T2 and T3 treatments were 7.3–8.6, 6.3–7.2, 5.4–6.3 and 4.9–5.6% CC, respectively, and 9.4–4.8, 16.1–8.1, 16.4–9.3 and 20.9–13.4% SWC, respectively. Whereas, the D-index and R2 of CC varied between 0.72 to 0.89 and 0.99 to 1.0, while in the SWC varied between 0.54 to 0.83 and 0.48 to 0.96 for the four irrigation treatments. The differences (S.D) in final biomass and grain yield were within the range of 0.23 to 4.45% and 0.30 to 1.46% between the measurement and simulation. Simulated WUEs of biomass and yield under different irrigation treatments ranged between 6.07 to 6.52 kg/m3 and 3.07 to 3.16 kg/m3, AquaCrop’s performance trends to underestimate the WUEs of biomass and yield, and emphasizes that the yield WUE increased linearly with water stress condition increased.