Based on the research and analysis of purple soil infiltration characteristics under four land utilization types in Three Gorges reservoir region

results show that: Compare to traditional farmland

the sand content of tree-crop intercropping land increases 21.37%

its silt and clay content decreases separately 11.63% and 4.14%

its overall porosity and non-capillary are 45.80 % and 8.96 %

which is the best of four land utilization types;The relationship between soil infiltration rate and time of four land utilization types can be expressed as Y=a X-b.The stable infiltration rate has obvious imparity among four land utilization types

and the result is bamboo forest land(55.89 mm/h)>tree-crop intercropping land(5.91 mm/h)>orchard(2.71 mm/h)>traditional farmland(1.87 mm/h);As the time to attain the stable infiltration rate

tree-crop intercropping land is 70 minutes later than traditional farmland

and the stable infiltration rate of the former is as 3.16 times as the latter

these show that tree-crop intercropping land can postpone process of runoff yield and increase moisture infiltration into soils

so it can be popularized in the scope of Three Gorges reservoir region.The ability of purple soil infiltration assumes the positive correlativity with sand

overall porosity and non-capillary

with clay

bulk gravity and the initial moisture has the inverse correlations.