Effect Of Stocking Rate On The Vegetation, Soil And Cattle Gain Weight In Stipa Krylovii Typical Steppe

The stocking rate is relationship between the number of animals and the grazing management unit utilized over a specified time period, which can be applied over a defined time period without deterioration of ecosystem. The stocking rate plays a very important factor for the grassland vegetation, soil, livestock production performance and the grass management in the grassland grazing system,. The study site located in Stipa krylovii typical steppe of the Elitu ranch of the Zhengxiangbai Banner of the Xilingol region. Four stocking rate:CK, light grazing (LG), moderate grazing (MG) and heavy grazing (HG) were used to determine the plant community and soil characteristics and livestock performance in2010and2011. The results were shown as follows:1. Stocking rate and year significantly affected on cover degree, height, and above-ground biomass of dominant species. The cover degree, height and above-ground biomass of the grassland communities and dominant species decreased with an increase of stocking rates.2. Surface soil moisture content and precipitation were positive correlation. Surface soil moisture content decreased with increasing stocking rate, whereas soil bulk density was opposite. Surface soil moisture content (0-10cm) significantly differed between years, and soil bulk density between years have an increasing trend.3. The content of soil organic matter, total nitrogen, quick-acting nitrogen, total phosphorus and total potassium reduced with the increasing stocking rate. Soil pH value increased and the content of quick-acting phosphorus in soil layer (10-20cm) decreased with the increasing stocking rate. The.content of quick-acting potassium in CK was significantly higher than in grazing plots. The content of soil organic matter, total nitrogen, quick-acting nitrogen and total potassium decreased with an increase of the soil depth in the vertical distribution4. The daily gain weight decreased with the increasing stocking rate. The appropriate sticking rate during grazing period was2.13sheep unit/hm2.