Study On Spatial-Temporal Variation Of Soil Infiltration Characteristics And Its Influencing Factors In Fengqiu Area

Relying on Fengqiu agro-ecological experiment station of Chinese Academy of Sciences, field disc infiltration experiments were carried out in Fengqiu district. It mainly analyzed the time variation characteristics of soil water infiltration under different land use patterns and different soil texture. The traditional statistics and geo-statistics were used to research the spatial structures variation of soil characteristics and water infiltration parameters on the typical cross section of the region. Furthermore, it aims to clarify the main influential factors of the space variation of soil water infiltration characteristics by comparing the differences of the space variation structures of water infiltration parameters in different soil texture and land use. This study could provide distribution accurate simulation to spatial-temporal variation of soil hydraulic characteristics and the hydrological processes at the flat area, also it could provide a reference for further develop water-saving irrigation and efficient utilization of water resources in China. The main conclusions were as follow:(1) Soil water infiltration with different texture and land use patterns in Fengqiu showed apparent seasonal variations characteristics within a year with the crop growth period. From autumn to the next spring, the soil water infiltration capacity decreased with the increase of soil bulk density, but it increased in crop vigorous growingstage. However, the soil infiltration capacity decreased at August and September when the rainfull period come. At the same time, there were some differences in time variation for soil water infiltration with different soil texture and land use. The30min cumulative infiltration, infiltration rate, stable infiltration rate and saturated hydraulic conductivity of Dahei Gang sand, were significantly higher than the other three soil texture, and presented a large time variation range. But the soil water infiltration parameters of the other soil with different textures had no significant differences, and the time variation range was basically similar. Under the four different land use patterns, to be affected by tilling, the surface soil infiltration capacity of the conventional tillage land is relatively strong. The soil water infiltration capacity of the land planting honeysuckle is weaker due to the surface soil crust in autumn and winter caused by artificial flower picking. The stable infiltration rate and saturated hydraulic conductivity of woodland soil with stabile structures are significantly higher than other land uses and the time variation range is also smaller.(2) By analyzing the soil characteristics and the space structure of water infiltration parameters on the typical cross section of the region, we can found that the soil bulk density and porosity variation were weak, and the surface initial water content belonged to moderate variability, the spatial autocorrelation is larger, and the spatial structure is better. However, the organic matter content has much weaker spatial correlation and its space variation can be greatly influenced by the randomness factor. The variation coefficients of30min cumulative infiltration, infiltration rate, stable infiltration rate and saturated hydraulic conductivity all showed moderate-intensity variations under the comprehensive influence of soil characteristics. And the30min cumulative infiltration, infiltration rate and stable infiltration rate can effectively reflect the space variation structure using spherical model, having moderate degree of spatial autocorrelation. But the space structure of the saturated hydraulic conductivity was weak.(3) Soil texture and land use patterns have a certain impact on the space variation of soil infiltration characteristics. As the soil texture changes from Dahei Gang sand to Li Zhuang loam, the soil texture became stickier and the water infiltration parameters mean value became lower, the range of soil sorptivety increased. And the spatial autocorrelation distance of stable infiltration rate and saturated hydraulic conductivity reduced. Under different land use patterns, the conventional tillage land has larger infiltration rate and variation range due to the impact of tillage on soil surface. The woodland soil has larger stable infiltration rate and average saturated hydraulic conductivity, the soil structure is stable, so the variation degree of water infiltration parameters is smaller. Seen from the spatial structure, the spatial autocorrelation distances of soil sorptivety under no-tillage land, the stable infiltration rate and saturated hydraulic conductivity rate in honeysuckle land are remarkably greater than that of soils with other land use, which showed that the effects of human activities on soil characteristics increases the space variation of soil water infiltration characteristics in field scales.