Soil quality

soil moisture and fertilizer preservation ability

and soil nutrient uptake ability are closely related to soil physical properties.In this study

42 soil samples were collected respectively in the 0—20 and 20—40 cm soil layers from seven desert sampling plots along descending precipitation gradient in Hexi Corridor region(from Minle County to Gaotai County).Saturated soil hydraulic conductivity was measured with the tension infiltrometer in field

and bulk density

porosity

and soil particle composition were determined by general methods in lab.Results show that physical properties of the desert soils are gradually degraded.With precipitation decreasing from 360 to 100 mm

silt and clay contents are reduced and sand content is increased.Increase in soil particle size may definitely result in soil dispersion and structure destruction

further increase soil bulk density

and reduce soil porosity and water holding capacity.The variance coefficients of saturated soil hydraulic conductivity in the surface and subsurface layers are 70.0% and 86.3%

respectively

both of which are the highest among the Cv values of all the physical properties.