河套灌区不同水肥处理对玉米生长影响的AquaCrop模型模拟

为探究内蒙古河套灌区玉米生长适宜的水肥管理方案,开展了不同灌水与施肥水平玉米田间试验。利用田间实测数据对AquaCrop模型进行了率定与验证,以此为基础,采用AquaCrop模型模拟分析了不同灌水和施肥条件下玉米产量和水分利用效率的变化规律。结果表明:(1)模型率定和验证过程中冠层覆盖度和生物量模拟值与实测值的R~2分别介于0.74～0.99,0.87～0.99;NRMSE分别介于4.55%～12.32%,5.77%～27.07%;E_(NS)分别介于0.90～0.99,0.85～0.99;各处理产量模拟值与实测值间R~2分别为0.99,0.97;NRMSE分别为4.59%,3.42%,E_(NS)分别为0.95,0.97;水分利用效率模拟值与实测值间R~2分别为0.81,0.86;NRMSE分别为6.75%,13.85%,E_(NS)分别为0.96,0.83。说明AquaCrop模型在河套灌区具有很好的适用性。(2)利用校验后的模型模拟了不同施肥水平下灌水量变化对玉米产量和水分利用效率的影响,当灌水量达270 mm后,继续增加灌水量,玉米产量和水分利用效率基本保持不变,甚至有所降低。(3)以稳产高效为目标,中肥条件下,灌水270 mm时玉米产量和水分利用效率均为各灌水量中的最优值。因此,推荐灌水270 mm、施肥375 kg/hm~2为研究区保障玉米稳产高效的最优灌溉施肥组合。

Simulation of Effects of Different Water and Fertilizer Treatments on Maize Growth with AquaCrop in Hetao Irrigated Area

In order to explore the water-fertilizer management strategy suitable for maize growth in the Hetao Irrigation District, Inner Mongolia, this study conducted a field experiment with different irrigation and fertilization levels. After the calibration and validationby observed data, the AquaCrop model was used to simulate the variation pattern of corn yield and water use efficiency (WUE) under different irrigation and fertilization levels. The results indicated:(1) The R² values of simulated and measured canopy coverage and biomass were 0.74~0.99 and 0.87~0.99, respectively, during model calibration and validation. The NRMSE values ranged from 4.55% to 12.32% and 5.77% to 27.07%, respectively, while the E_NS ranged from 0.90 to 0.99 and 0.85 to 0.99 respectively. The R² values between the simulated and measured output values were 0.99 and 0.97, respectively, and NRMSE were 4.59% and 3.42%, and E_NS were 0.95 and 0.97, respectively. The R² between the simulated and measured WUE were 0.81 and 0.86, respectively, and NRMSE were 6.75% and 13.85%, and E_NS were 0.96 and 0.83, respectively, indicating that AquaCrop model had a good applicability in the Hetao Irrigation District. (2) The verified model was used to simulate the effects of irrigation changes on maize yield and WUE at different fertilization levels. The results showed that when irrigation rate reached 270 mm and continued to increase, the maize yield and WUE remained basically unchanged or even decreased. (3) With stable yield and high efficiency as the target, under the medium fertilization, the optimal corn yield and WUE were given at 270 mm of irrigation. Therefore, we recommend 270 mm irrigation, 375 kg/hm² fertilizing as the best combination to ensure the stable-yield and high-efficiency in the studied area.