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土壤中优先流的存在会造成肥料利用率降低以及土壤深层甚至地下水污染。为确定土壤初始含水率对优先流的影响,通过室内含大孔隙土柱定水头入渗实验,以长武黑垆土及渭河砂土为研究对象,分析不同土壤初始含水率对优先流的影响。结果表明:1)相同质地,当土壤初始含水率大于其斥水性的峰值含水率时,湿润锋运移深度随着土壤初始含水率的增大而增大,反之湿润锋运移深度随着初始含水率的增加而减少,不同质地土壤湿润锋运移速度随土壤粉粒质量分数升高而减慢;2)累积入渗量受到土壤储水性及斥水性的双重影响,导致与湿润锋的运移趋势并不一致,黑垆土对照CK组及优先流O-C-30组(除7.04%含水率外)累积入渗量随着土壤初始含水率的增大而减小,渭河砂土CK组及O-C-30组均呈现2阶段特征,累积入渗量先随着土壤初始含水率的增加而减少,之后随土壤初始含水率的增加而增加;3)Kostiakov入渗模型能很好地拟合累积入渗量随时间的变化过程,适用于存在优先流的土壤入渗模拟。该研究结果对土壤优先流水分模拟具有一定的指导意义。
The presence of preferential flow in the soil can result in lower fertilizer use efficiency and in deep soil and even groundwater contamination. In order to determine the influence of initial soil water content on preferential flow, the effects of different initial soil moisture contents on preferential flow were analyzed through indoor infiltration experiments with macroporosity soil columns and Changwu black soil and Weihe sandy soil. . The results show that: 1) When the initial soil moisture content is higher than the peak water content of the water-repellent soil, the migration depth of wetting front increases with the increase of soil initial moisture content. On the contrary, The moisture transport rate decreases with the increase of soil moisture content, and the transport speed of wetting front of soil with different texture slows down with the increase of soil particle mass fraction; 2) The cumulative infiltration is affected by both soil water storage and water repellency, The tendency of migration is not the same. The cumulative infiltration of black soil CK and preferential OC-30 (except for 7.04% water content) decreases with the increase of soil initial moisture content. CK and OC -30 groups showed a 2-stage characteristic. The cumulative infiltration rate decreased with the increase of soil initial moisture content and then increased with the increase of soil initial moisture content. 3) The Kostiakov infiltration model could well fit the cumulative The change of seepage volume with time is suitable for simulation of soil infiltration with preferential flow. The results of this study have certain guiding significance for the simulation of soil preferential flow.