Effects Of Grazing Intensity On Community Characteristics And Soil Chemometrics In Desert Steppe

Grazing is one of the main ways of utilization in desert grassland.Taking Stipa Breviflora Desert Steppe in Xilinguole League of Inner Mongolia as the research object,three grazing gradient experiments were set up,including zero grazing,moderate grazing and heavy grazing.The response of community height,coverage,density,community biomass,community diversity,soil nutrients and the chemometric characteristics of vegetation and soil to grazing was studied and analyzed in order to determine the reasonable grazing intensity of desert steppe.It provides theoretical basis for the rational utilization and sustainable development of grassland.The main results are as follows:1.Grazing reduced community height,coverage,density and biomass.Shannon-winener diversity index and Simpson index decreased with the increase of grazing intensity,and Pielou evenness index was the largest under moderate grazing conditions.Throughout the growing season,the height,coverage,density and biomass of grazing intensity treatments in August and September were higher than those in other months.2.Grazing increased the total N content of the community,but the total C and P content of the community did not change significantly,and the overall trend was decreasing.C/N decreased with the increase of grazing intensity,and the ratio of C/P to N/P was higher under moderate grazing.The total C and P of the community changed in an inverted "V" pattern with the passage of the season,while C/N and C/P changed in a "V" pattern.There is a linear positive correlation between N-P and a linear negative correlation between P-N and P.The fitted R2 between N-C/N and P-C/P reached 0.95,which showed a significant correlation.3.Grazing had no significant effect on the content of total phosphorus and available phosphorus in soil;grazing increased the content of available potassium,organic carbon and total nitrogen;the content of total potassium and total nitrogen decreased with the increase of soil depth.0-10 cm topsoil has the highest available potassium content.Soil total C was positively correlated with total P,and soil total C was positively correlated with C/N and C/P.Soil total P was negatively correlated with C/P and N/P.Soil C/P was positively correlated with N/P(P<0.01).