The Change Of Soil Biology Character And The Evaluation Of The Soil Health In NingXia Desert Steppe Under The Different Rotational Grazing

The research object was the desert steppe of Ningxia, Under the ungrazed (CK) and continuous grazing (CG), two districts rotational grazing (TG), four districts rotational grazing (FG) and six districts rotational grazing (SG), the changes of microbes and enzyme activity of soil, it analyzed the soil microorganism, enzyme activity, the correlation between physical and chemical properties, the evaluation of health of grazing grassland. The results showed that:In CK、CG、TG、FG、SG, soil microorganisms were given priority to actinomycetes, bacteria took the second place, fungus was minimal. In 0 to 30 cm soil layer, the total number of microbes in SG, actinomyces and bacteria were the largest; FG next and CG was minimal. As the soil layers deepen, total microbial quantity was on the decline, In soil crust, the microbial total quantity was the most in TG; bacteria quantity of CG was the highest, the total actinomyces TG was the most.The microbial biomass C and N content under different rotational grazing were extremely significant difference (P< 0.01).0 to 30 cm soil microbial biomass C of SG was the largest, and the microbial biomass N of FG was the biggest; Microbial biomass C layer phenomenon in CK. CG had the highest soil microbial biomass C content in the crust, and FG microbial biomass N content was the highest.Enzyme activity in different rotational grazing was extremely significantly different (P< 0.01). SG dehydrogenase activity and urease activity were the highest. Invertase and catalase activity were the highest in TG. The phosphatase activity of CG was the highest. As the soil deepening, the enzyme activity declines (P< 0.01).The density of CG was minimum, and the porosity and moisture performance was good. In SG and CK, the results were different; Soil particle composition is given priority with fine sand, silt and sand in the second, coarse sand was tiny; soil physical crust coverage most, lichen-algae crust, moss crust at least.CK maximum total coverage of the three types of soil crust, SG next and CG was minimal. Soil total nitrogen in CG was the largest and TG next, FG was minimum. Soil organic in SG was the largest, TG was minimal. Alkaline hydrolysis nitrogen in CK was the largest, the largest available P in CG.The correlation between the soil biological characteristics and soil physical and chemical properties:The Catalase and the microbial biomass carbon have significantly positive correlation.The actinomycetes and the urease have significantly positive and strong correlation with the microbial biomass carbon; the bulk density and the phosphatase have significantly negative correlation relationship.the available P and phosphatase have significantly positive correlation with catalase. Available K and microbial biomass carbon have significantly positive correlation with fungi.Through principal component analysis (pca) and the evaluation result of the subordinate function analysis, they got the soil health performance:SG> FG> TG> CK> CG.