水温对滴灌土壤水分入渗特性的影响

Effects of water temperature on soil water infiltration characteristics under drip irrigation

为了解水温对滴灌土壤水分入渗特性的影响,通过室内滴灌入渗模拟试验,研究了滴灌条件下西安粉壤土在不同水温(4,20,30,40℃)时的水分入渗特性.结果表明:水平和垂直湿润锋运移距离均随着入渗时间的延长而增大,相同入渗历时,入渗水温越高,滴头流量越大,入渗的水量越多,湿润锋运移距离越大;分别建立了滴灌条件下不同温度水分入渗时水平和垂直湿润锋运移距离与入渗时间和水温的关系模型,其相关系数均大于0. 97.湿润体的平均含水量与入渗水温和时间密切相关,入渗水温越高,土体平均含水量越小;含水率等值线随着到滴头距离由近到远而从疏到密分布,离滴头越近,土壤含水率越高;随着入渗水温的不断升高,入渗到同一深度所需时间逐渐减小,对土层温度的影响越大,在入渗400 min内以土面至土面以下15 cm深度范围内的土温变化更为突出.结论可为发展滴灌技术提供参考依据.

In order to determine the effect of different water temperature on soil water infiltration cha-racteristics of drip irrigation,the research about Xi′an silty loam water infiltration was carried out by drip irrigation experiment at the water temperature of 4,20,30 and 40℃.The results show that:The migration distance of the wetting front increases with the infiltration time.At the same infiltration time,with the water temperature rising,the migration distance of the wetting front and dripper discharge will increase.The model of horizontal(vertical)migration distance of the wetting front,the infiltration time and water temperature are established under the condition of drip irrigation water infiltration at different water temperatures,its correlation coefficient is greater than 0.97.The average moisture content of the wetted body is closely related to the infiltration water temperature and time.The higher the infiltration water temperature,the smaller the average water content of the soil.The isoline map of soil moisture content in the wetted body are closer to the drip distance from near to far and from the sparse to the dense distribution.With the infiltration of water temperature continues to rise,infiltration into the same depth of time gradually reduces and has a greater impact on soil temperature.The change of soil layer temperature in the depth range of 15 cm below soil surface is more prominent within 400 minutes of infiltration time.The conclusion provides the reference for further studies of drip irrigation technology.