基于AquaCrop模型的大豆灌溉制度优化研究

【目的】 探究AquaCrop模型在关中地区的适用性,寻求大豆在不同降水年型下最适宜的灌溉制度。【方法】 用田间试验实测数据对该模型进行校正,并用校准后的模型模拟1961—2019年内所有3种不同降水年型14种灌溉制度下的大豆产量和水分利用效率。【结果】 AquaCrop模型模拟田间产量最高处理的冠层覆盖度的决定系数(R ²)、均方根误差（RMSE）、标准均方根误差(NRMSE)及Nash效率系数(EF)分别为0.96、7.15%、11.03%和0.94;模拟值与实测值生物量的决定系数（R ²）、均方根误差（RMSE）、标准均方根误差（NRMSE）及Nash效率系数（EF）分别为0.99、526.04 kg·hm^-2、14.45%和0.97;最终产量模拟的决定系数（R ²）、均方根误差（RMSE）、标准均方根误差（NRMSE）及Nash效率系数（EF）分别为0.97、49.98 kg·hm^-2、1.74%和0.82,各处理的冠层覆盖度和生物量实测值与模拟值的R ²均大于0.95,说明AquaCrop模型可以较好地模拟关中地区大豆的生长发育动态与产量。结合模型模拟结果可知,大豆作物需水量平均值为398.2 mm,各个生育时期的需水量差异较大,分枝期需水量为127.8 mm,开花-结荚期需水量为212.6 mm,鼓粒期的需水量为57.7 mm。结合对3种不同降水年型进行不同灌溉制度模拟后发现,大豆开花-结荚期为需水关键期,该生育时期水分供应情况影响大豆的最终产量。在湿润年可以不灌水;平水年和干旱年仅在开花-结荚期分别灌溉45和70 mm可实现最高产量（2 699、2 486 kg·hm^-2）和最大水分利用效率（0.74、0.7 kg·m^-3）。【结论】 该地区大豆灌溉制度,应以不同降水年型分布情况为基础对大豆灌溉制度进行选择,可保证大豆具有较高的产量和水分利用效率,可作为关中地区大豆灌溉制度的参考依据。

Research on Soybean Irrigation Schedule Based on AquaCrop Model

【Objective】 The aim of this study was to evaluate the applicability of AquaCrop model in the Guanzhong Plain and to explore the optimal irrigation schedule for summer soybean under various precipitation year types. 【Method】 AquaCrop model was calibrated by using field experiment data and then used to simulate soybean yield and water use efficiency under 14 irrigation systems with three different precipitation years from 1961 to 2019.【Result】 The determination coefficient (R²), root mean square error (RMSE), standard root mean square error (NRMSE) and Nash efficiency coefficient (EF) of simulated and measured soybean yield under the highest yield treatment by AquaCrop model were 0.96, 7.15%, 11.03% and 0.94, respectively, which of simulated and measured biomass values were 0.99, 526.04 kg·hm^-2, 14.45% and 0.97, respectively. A good agreement was observed for final yield simulation with the R², RMSE, NRMSE, and EF were 0.97, 49.98 kg·hm^-2, 1.74% and 0.82, respectively. The R² values of the measured and simulated canopy coverage and biomass of each treatment were greater than 0.95, indicating that the AquaCrop model could better simulate the growth and development dynamics and yield of soybean in Guanzhong Plain. Combined with the simulation results of the model, the water requirements of the whole growth period of soybean were 398.2 mm. The water requirements of each growth period were significantly different for three precipitation years. The water requirements in the soybean branch stage were 127.8 mm, the water requirements of flowering and podding stage were 212.6 mm, and those of grain filling stage were 57.7 mm. Combined with the simulation of different irrigation systems for three different precipitation years, it was found that the flowering and podding period stage was the key period of water demand, and the water supply in this growth period affected the final yield of soybean. Simulation resulted showed that no irrigation was needed in wet years. In the normal and dry years, it was recommended to irrigate only 45 mm and 70 mm at flowering and podding stage to achieve the maximum yield of 2 699 kg·hm^-2 and 2 486 kg·hm^-2, and the maximum water use efficiency of 0.74 kg·m^-3 and 0.7 kg·m^-3, respectively. 【Conclusion】 To ensure higher soybean yield and water use efficiency, the soybean irrigation schedule in this region should be determined based on the distribution of different precipitation years, which could be used as a reference for the soybean irrigation system in the Guanzhong Plain region.