温室膜下滴灌条件下黄瓜需水规律研究

根据试验区温室黄瓜生育期环境因子实测资料,采用土壤水量平衡原理模拟了黄瓜生育期土壤含水量的变化过程,以模拟计算的土壤含水率与实际测试的土壤含水率的误差平方和最小为目标函数来确定温室膜下滴灌条件下的作物系数和作物需水量。结果表明,黄瓜生长期土壤含水率的模拟值和实测值较为吻合,两者相对误差在10%以内。作物系数在生长前期是逐渐变大,在作物生长旺盛时期作物系数达到最大值,随后逐渐减小,与作物叶面积指数的变化规律一致。温室黄瓜需水量在生长期的前期随时间的变化幅度较小,变化为1.5~3.5mm/d;中期随时间的变化幅度较大,变化为0.2~7.5mm/d;后期随时间的变化幅度又变小,变化为3.5~7.2mm/d。

A Study on Cucumber Water Requirement with Drip Irrigation under Plastic Mulch in Greenhouse

According to the test data of environmental factors in greenhouse during cucumber growth period,the change of soil mois-ture was simulated by the method of the water balance equations.The obj ective functions was to minimize the quadratic sum of the difference between simulated soil moisture and tested soil moisture to calculate the crop coefficients and the water requirement with drip irrigation under plastic mulch in greenhouse.The results showed that the simulated and tested data of soil moisture values dur-ing cucumber growth period were similar with the relative error of 10%;crop coefficients in the early stage of growth gradually in-creased;crop coefficients in the crop growth period reached the maximum,and then gradually decreased.The change regulations of crop coefficient and leaf area index were consistent;the water requirement variation amplitude from 1.5~3.5 mm/d of cucumber in greenhouse in the early growth period was small;the water requirement variation amplitude from 0.2~7.5 mm/d of cucumber in the medium period was greater;the water requirement variation amplitude from 3 .5~7 .2 mm/d of cucumber in the later growth was small.