Infiltration is an important process for the exchange of rain water

surface water

soil water

and ground water. It has great significance to the hydrological cycle of a watershed. The water-wind erosion crisscross region initiates the most serious soil and water loss on the Loess Plateau

and studies on the soil infiltration properties and its spatial variability in this region will do help to understand the process of the soil erosion and improve the precision of the watershed hydrological model. On a natural slope (375 meters long) in the Liudaogou catchment

which is typical of the water-wind erosion crisscross region

stable infiltration rate and cumulate infiltration capacity within the initial 30 min were measured with double-ring infiltrometer at 57 sampling plots

and the traditional statistical method and geostatistical method were adopted to study the spatial variability of the soil infiltration properties. The results indicate: (1) The coefficients of variation (C_v) of stable infiltration rate and cumulate infiltration capacity within the initial 30min are 0.480 and 0.404

respectively

and the variation extent on the slope of these two parameters shows medium variation. (2) The theoretical variogram and the experimental variogram of these two parameters match very well

and the ranges are 126 m and 226 m respectively

the nugget values are both above 0

which indicates that some spatial variability may probably exist in a smaller scale than the sampling interval and this means that the sampling interval should be shortened.