基于AquaCrop模型的南疆无膜滴灌棉花灌溉制度优化

Irrigation Scheduling Optimization of Drip-irrigated without Plastic Film Cotton in South Xinjiang Based on Aqua Crop Model

为探究AquaCrop模型对南疆地区无膜滴灌棉花种植的适用性、寻求最优灌溉制度,以2018—2019年田间实测数据对模型进行校验,并利用校准模型分别模拟2种不同灌水情景下的棉花冠层覆盖度、生物量及产量的变化规律。结果表明:采用AquaCrop模型模拟2019年冠层覆盖度的均方根误差(RMSE)、拟合指数(d)、标准均方根误差(NRMSE)及决定系数(R2)分别为6.03%、0.12、13.08%和0.97,生物量模拟的各参数分别为810 kg/hm^(2)、0.93、6.41%和0.80,产量模拟的各参数分别为751 kg/hm^(2)、0.84、14.02%和0.87,说明AquaCrop模型可以较好地模拟南疆地区无膜滴灌棉花的生长与产量。基于1960—2019年的气象数据,利用AquaCrop模型对无膜滴灌棉花进行情景模拟:灌水周期相同时,无膜滴灌棉花产量随灌溉定额的增加呈先增加、后减小的变化趋势,总灌水量为7 200 m3/hm^(2)时产量达到最大值(5 398 kg/hm^(2)),水分利用效率(WUE)为0.75 kg/m3;灌溉定额相同时,无膜滴灌棉花产量随灌水周期的增加而增加,总灌水量为5 400 m3/hm^(2)、灌水周期为5 d时,产量达到最大值(5 315 kg/hm^(2))、WUE为0.98 kg/m3。研究表明,灌水周期5 d、灌溉定额540 mm的灌溉制度可保证无膜滴灌棉花具有较高的产量和水分利用率,可作为无膜滴灌棉花的参考灌溉制度在南疆地区推广应用。

To investigate the applicability of the Aqua Crop model to drip-irrigated cotton without plastic film in South Xinjiang,and develop the optimal irrigation scheduling,the Aqua Crop model was calibrated and validated by using the dataset collected in 2018 and 2019 seasons,then the model was used to simulate canopy cover (CC),plant biomass,and cotton yield under two different irrigation scenarios.The results showed that the root mean square error (RMSE),the fit index (d),the standard root mean square error (NRMSE) and the determination coefficient (R2) between the simulated and measured values of CC were 6.03%,0.12,13.08%and 0.97,and the corresponding values for plant biomass and cotton yield were 810 kg/hm^(2),0.93,6.41%and 0.80,and 751 kg/hm^(2),0.84,14.02% and 0.87,respectively,indicating that the Aqua Crop model could be used as a feasible tool to predict cotton growth and yield response to irrigation under drip irrigation without plastic film in this region.The scenario simulation was carried out by using the Aqua Crop model with the meteorological data from 1960to 2019.The scenario simulation results indicated that under the condition of the same irrigation frequency,the cotton yield was increased first and then decreased with the increase of the irrigation quota,and the maximum yield of 5 398 kg/hm^(2) was obtained with the total irrigation amount of 7 200 m3/hm^(2),and the water use efficiency (WUE) was 0.75 kg/m3.While under the condition of the same irrigation quota,the cotton yield was increased with the increase of irrigation frequency,and the maximum yield of5 315 kg/hm^(2) was achieved with the irrigation frequency of 5 d and the total irrigation amount of 5 400 m3/hm^(2),and WUE was 0.98 kg/m3.It could be concluded that the high yield and WUE of dripirrigated cotton without plastic film could be ensured by the irrigation scheduling with the irrigation frequency of 5 d and the total irrigation amount of 5 400 m3/hm^(2),which could be used as a reference irrigation scheduling for application of drip-irrigated cotton without plastic film in South Xinjiang.