冻融期不同时间灌水对土壤水热影响的试验研究

Experimental Study on the Influence of Irrigation at Different Time on Soil Moisture and Heat During Freeze-Thaw Period

为了揭示冻融期不同时间灌水对土壤水分运移和温度分布的影响,设置了未灌水裸地L0和冻融期7个不同时间灌水地块(即L1、L2、L3、L4、L5、L6和L7,灌水1次,灌水量225 m^(3)/hm^(2)),跟踪监测冻融期不同地块土壤剖面温度和土壤含水率。结果表明:灌水对0~20 cm的土壤含水率和温度影响显著,不稳定冻结阶段初灌水对整个冻融期的土壤温度具有明显的降温效应,较L0降低2~4℃;当地表冻层形成并稳定时,灌水对土壤温度具有一定的增温效应,较L0提高1~2℃。冻融期较早的灌水对土壤剖面0~60 cm的储水效果较好,不稳定冻结初期灌水2~10 cm的土壤含水率L1较L0提高69.0%;稳定冻结阶段灌水对0~25 cm土壤平均含水率提高44.5%,消融解冻阶段灌水0~40 cm土壤平均含水率较L0提高19.0%~34.0%。稳定冻结阶段灌水具有较为积极的水热效应。

In order to reveal the influence of irrigation at different time during the freeze-thaw period on transport of soil moisture and distribution of temperature,in this study,the unirrigated bare land labeled L0 and 7 plots irrigated at different times during the freezing and thawing period(labeled L1,L2,L3,L4,L5,L6 and L7,irrigated only once with the quota of 225 m^(3)per hm^(2))were set,and the soil profile temperature and soil moisture content of different plots during the freeze-thaw period were monitored.The results showed that irrigation at different time had a significant effect on the soil moisture content and temperature at the depth of 0 to 20 cm,and the initial irrigation in the unstable freezing stage had a significant cooling effect on the soil temperature during the freeze-thaw period;when the surface frozen layer was formed,the irrigation had a significant effect on improving the soil temperature.Earlier irrigation had a better effect on the water storage at the depth of 0 to 60 cm.Irrigation in the initial stage of unstable freezing increased the soil moisture content by 69.0%at the depth of 2 to10 cm;irrigation in the stable freezing stage had an average effect on soil at the depth of 0 to 25 cm and the water content was increased by44.5%;the irrigation during the thawing stage increased the average water content at the depth of 0 to 40 cm soil by 19.0%~34.0%.Irrigation in the stable freezing stage had a more positive effect on soil moisture and soil temperature.