基于AquaCrop模型的夏玉米生长模拟及灌溉制度优化

Growth simulation and optimization of irrigation scheme forsummer maize using AquaCrop model

为评价AquaCrop模型在关中地区的适用性并寻求最佳的灌溉制度,对夏玉米在不同灌溉与施氮水平下的生长进行模拟和验证,并利用校验后的模型研究了3种不同降雨年型以及11种灌溉模式下夏玉米产量和水分利用效率的变化特征。结果表明:AquaCrop模型可以较好地模拟关中地区不同灌溉与施氮水平下夏玉米产量和生物量,模型模拟的产量与实测值之间的决定系数( R 2 )、均方根误差( RMSE)、标准均方根误差(NRMSE)、符合度指数(d)和纳什效率系数(E NS )分别为0.919、0.249 t·hm^-2 、4.112、0.977和0.915;对于地上部生物量,模拟值与实测值的 R 2、RMSE、NRMSE、d和E NS 分别为0.860、0.977 t·hm^-2 、6.407、0.933和0.694。利用校验后的模型分析了试验区内3种不同降水年型条件下11种灌溉模式的夏玉米产量和水分利用效率的变化特征,依据模拟结果及夏玉米生理需水规律,同时为了实现高产和高水分利用效率,得出不同年型的优化灌溉制度为:若能保证出苗整齐,湿润年可不灌水,此时也能获得较高产量和水分利用效率;平水年推荐在拔节期灌水60 mm,能节约50%水资源,亦能保证稳产;干旱年推荐在拔节期和抽雄期各灌水60 mm,可获得高产和高水分利用效率。

In order to evaluate the suitability of the AquaCrop model in the Guanzhong area and explore the best irrigation scheme, the model was used to simulate and validate the growth of summer maize under different irrigation and nitrogen levels.Then,we used the calibrated model to study the changes of summer maize yield and water use efficiency under 11 kinds of irrigation scenarios under three precipitation types.The results showed that the AquaCrop model well predicted the summer maize grain yield and biomass under different irrigation and nitrogen levels in Guanzhong.The coefficient of determination( R 2 ), root mean square error( RMSE ), normalized root mean square error( NRMSE ), consistency( d ) and model efficiency( E NS ) between the simulated and observed values of yield were 0.919,0.249 t·hm^-2 ,4.112,0.977 and 0.915 for all treatments, respectively;As for biomass, R 2, RMSE,NRMSE,d and E NS between the simulated and observed values were 0.860,0.977 t·hm^-2 ,6.407,0.933 and 0.694 for all treatments,respectively.Then using the calibrated model to study the changes of summer maize yield and water use efficiency in 11 kinds of irrigation scenarios under three precipitation types.Based on the simulation results and combined with the physiological water requirement of summer maize, the water requirements during the jointing and tasseling stages should be emphasized.Optimized irrigation scheme for different precipitation year are: if we can guarantee good seedling emergence, irrigation is not needed during the wet year;in the normal year, 60 mm can be irrigated during the jointing period;in the dry year, 60 mm of irrigation water should be applied during jointing and tasseling.These schemes will guarantee the stable production and high yield.