降雨集流渗灌系统室内模拟土壤水分运动研究

为解决宁南山区旱地经济林干旱缺水的现状及小降雨(4~16 mm)无法入渗到根系(20~40 cm)分布范围,设计了一种降雨集流渗灌装置,通过室内土箱试验,以降雨量作为控制因子,研究不同雨量条件下径向和垂向土壤水分的运动特征。结果表明:随雨量增加累计入渗量逐渐增大,入渗速率逐渐减小;不同雨量条件下土壤含水率增量在垂向0~40 cm范围内随土层深度的增加呈先增加后减小的趋势,径向沿距渗灌器距离的增加逐渐减小;灌水结束24 h后土壤水分高含水率区主要分布在垂向20~40 cm和径向0~20 cm,湿润体大致呈半椭球体;集流渗灌器明显提升了小降雨的利用,使经济林主要根系分布范围(20~60 cm)内,土壤含水率明显增加,有利于缓解经济林生育期缺水,促进其生长,该研究结果可为集流渗灌器在田间推广应用提供可靠的数据支撑。

Simulation of Soil Moisture Movement in Rainfall Collecting Infiltration Irrigation System

In order to solve the problems of lacking water of economic forest in southern Ningxia and no infiltration to the root system(20~40 cm)distribution under light rain(4~16 mm),a rain collecting device was designed and the horizontal and vertical movement characteristics of soil moisture under different rainfall conditions was studied through the indoor soil box test with rainfall as the control factor.The results showed that with the increase of rainfall,the cumulative infiltration amount increased gradually,and the infiltration rate decreased gradually.Under different rainfall conditions,the increment of soil water content in the vertical range of 0~40 cm increased first and then decreased with the increase of soil depth,and the radial distance from the infiltration irrigation device gradually decreased.After 24 h irrigation,the high moisture content areas were mainly distributed in the vertical direction of 20~40 cm and the radial direction of 0~20 cm,and the wetted body was roughly semi-ellipsoid.The water content of soil was significantly increased within the main root distribution range(20~60 cm)of the economic forest,which was conducive to alleviating the water shortage in the growth period of the economic forest and promoting its growth.The results of this study can provide reliable data support for the application of the irrigation device in the field.