Abstract: This research aims to clarify the effects of un-grazing (UG) on the nutrients composition of soil in Anabasis salsa desert (6 years of enclosure) and Haloxylon persicum desert (7 years of enclosure) and use the method of combination field survey with the laboratory analysis and studied the response of desert the nutrients composition of soil, which provide a scientific basis and management for the local animal husbandry. The results showed that: 1) The soil nutrient concentrations in A. salsa desert were significantly higher than in the H. persicum desert. 2) In A. salsa desert, short-term grazing exclusion (GE) had little effect on the carbon density, total N, total P and total K of the soil system. 3) In H. persicum desert, the carbon density increased by 43.46% (P>0.05) with GE, but total P and total K were decreased by 33.53% (P<0.05) and 60.30% (P<0.05), respectively. In summary, short-term GE has a small effect on soil properties in A. salsa desert, and promoted increased soil carbon density in H. persicum desert, but led to a decline in the total P and total K in H. persicum desert. The results showed that the GE effect differs between desert vegetation types and soil types.

Key words: short-term un-grazing, Haloxylon persicum desert, Anabasis salsa desert, nutrients composition of soil