紫花苜蓿耗水规律及灌溉制度优化研究

为研究河套灌区紫花苜蓿的耗水规律,同时对现有灌溉制度进行优化,在田间试验的基础上,设置不同灌水水平对前两茬苜蓿进行了研究。结果表明:现蕾期和开花期是紫花苜蓿耗水的旺盛阶段,该阶段土壤水分亏缺会直接影响苜蓿产量的形成。通过多元线性回归的方法求解得到了两茬紫花苜蓿各生育期的敏感性系数,分别在0.103~0.731和0.041~0.375之间,且以现蕾期和开花期为最大,说明这两个生育阶段为苜蓿生长的关键阶段。以Jensen模型为基础,采用最小二乘法初步优化了两茬紫花苜蓿生育期内的灌溉制度,第1茬灌溉定额以1 400 m3/hm~2为宜,第2茬以2 300 m3/hm~2为宜,两茬灌水次数分别以4次和5次为最优。

A Study on Water Consumption Law and Irrigation Regime for Alfalfa

In order to study the water consumption law of Alfalfa and optimize the existing irrigation regime in Hetao Irrigation District,different irrigation levels are set up to study the first two crops alfalfa based on field experiment.The results show that bud stage and flowering stage are the vigorous stages of alfalfa;in this two stages,the soil water deficit will directly affect the yield of alfalfa;the sensitivity index are 0.103~0.731 and 0.041~0.375 for the first two crops alfalfa,and it is the largest at the bud stage and flowering stage,which means that the two growth stages are the key stages for the growth of alfalfa.Based on Jensen model,the least squares method is used to optimize the irrigation regime of the two crop alfalfa.It is proposed that the irrigation quota suitable for the first crop is 1 400 m+3/hm+2,and for the second crop is 2 300 m+3/hm+2;the optimal irrigation times is 4 and 5 times,respectively.