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

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.