不同地表覆盖下冻融土壤入渗能力及入渗参数(英)

    Infiltration capacity and parameters of freezing and thawing soil under different surface coverages

    • 摘要: 为了研究不同地表覆盖下冻融土壤入渗能力的差异和入渗参数的变化规律,进行了一系列裸地、地膜覆盖地和秸秆覆盖地土壤田间入渗试验。研究表明,冻土的入渗能力主要受冻层的控制,冻层是入渗水分的控制界面,土壤冻融特征差异是影响不同地表覆盖下土壤入渗能力大小的主导因素。冻融土壤的水分入渗过程可用三参数考斯加科夫土壤入渗经验模型描述。水分入渗开始 1 min内的累积入渗量大小随着冻层厚度和密实度的增加而减小,随着土壤冻融循环次数增加而增大;入渗能力的衰减率随着冻层厚度和密实度的增加而减小;稳定入渗率大小主要取决于土壤冻结状态和入渗锋面处的水力特性。三入渗参数均与土壤含水率和冻结深度有关,不同地表覆盖下的土壤入渗参数随着冻层深度的增加而减小,随着土壤的消融解冻而增大。该研究成果对农业生产实际和水土保持具有重要的指导意义。

       

      Abstract: In order to discover the differences of infiltration capacity and the variation of infiltration parameters of freezing and thawing soil under different surface coverages, a series of field soil infiltration tests of bare plot, plastic film mulched plot and corn straw mulched plot had been conducted. The results showed that the infiltration capacity of frozen soil was mainly affected by the frost layers, and the frozen layers were the control interface of the infiltrating water. The freeze-thaw characteristic was the main factor which influences the infiltration capacity under different surface coverages. The process of water infiltrating into freeze-thaw soil could be expressed by the three parameters Kostiakov empirical model. The accumulated infiltration within one minute decreased with increasing of thickness and density of frozen layers and increased with increasing the numbers of freeze-thaw cycles, the decay rate of soil infiltration capacity decreased as the thickness and frost density increased, the stable infiltration rate changed with the changes of soil freezing status and the hydraulic properties at the infiltration front. The three parameters of soil infiltration were related to soil moisture and frost depth. In all plots the infiltration parameters gradually declined with increasing the frost depth, and recovered as the soil thawed. The results have great significance for agricultural production and soil-water conservation.

       

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