基于双作物系数法的新疆覆膜滴灌夏玉米蒸散量估算

Evapotranspiration Estimation of Summer Maize with Plastic Mulched Drip Irrigation Based on Dual Crop Coefficient Approach in Xinjiang

为评估双作物系数法计算干旱区部分覆膜滴灌条件下夏玉米蒸散量的可靠性,于2016—2017年在新疆阿克苏地区开展了夏玉米蒸散量测坑试验研究,试验根据定灌水周期(W1、W2、W3)和变灌水周期(W4、W5)共设置5个处理,并分别采用稳定碳同位素法和水量平衡法,对双作物系数模型计算的夏玉米蒸腾量和蒸散量进行了验证。结果表明,双作物系数法计算的蒸散量与水量平衡法测定的蒸散量呈现出较好的相关性,全生育期蒸散量模拟值与实测值的均方根误差在10 mm左右。双作物系数法计算的蒸腾量与稳定碳同位素法测得的耗水量亦呈现出较好相关性,模拟值与实测值的均方根误差在20 mm左右。通过回归系数(b)、一致性指数(d)及均方根误差(RMSE)的分析,认为双作物系数法可以估算并区分局部覆膜滴灌条件下干旱区夏玉米蒸散量,且2016年和2017年夏玉米全生育期内估算土壤蒸发量分别占蒸散量的21. 33%和23. 97%,作物蒸腾量分别占蒸散量的78. 67%和76. 03%。

In order to evaluate the reliability of dual crop coefficient approach on calculating evapotranspiration of summer maize with mulched drip irrigation in arid region,the evapotranspiration of maize was measured by stable carbon isotope technique and water balance methods in measurement pits in 2016 and 2017.Five treatments were set up according to fixed irrigation cycle(W1,W2 and W3)and variable irrigation cycle(W4,W5)and the corresponding values were also calculated by dual crop coefficient approach.Experimental results showed that evapotranspiration calculated by dual crop coefficient approach had positive correlation with those values obtained by water balance methods,and the root mean square error was about 10 mm.The crop transpiration calculated by dual crop coefficient approach also had positive correlation with those values obtained by stable carbon isotope technique,and the root mean square error was about 20 mm.By calculation and analysis on the root mean square error,regression coefficient and consistency index,it can be concluded that dual crop coefficient approach was an effective method to calculate and distinguish evapotranspiration of summer maize with partial mulched drip irrigation in arid region.In whole growing season of summer maize,the simulated soil evaporation accounted for 21.33%and 23.97%of evapotranspiration and plant transpiration accounted for 78.67%and 76.03%of evapotranspiration in 2016 and 2017,respectively.