Effects Of Different Stocking Rates On Soil Enzymes In Stipa Breviflora Desert Steppe

In order to reveal the effects of different stocking rates on soil enzymes' activity of desert steppe.Study on the Stipa breviflora desert steppe in Inner Mongolia,to analyse the activity of soil enzymes with different stocking rates(No Grazing,CK;Light Grazing,LG;Moderate Grazing,MG;Heavy Grazing,HG)and different soil depths(0-10 cm,10-20 cm),to discuss the changes of underground and above-ground biomass of vegetation and the root shoot ratio(R/S),soil pH,electricity conductivity(EC),total carbon(TC),total nitrogen(TN),total sulfur(TS),organic carbon(SOC),alkali-hydrolyzable nitrogen(AN),available phosphorus(AP),available potassium(AK)and soil C:N with different stocking rates,and the relativity between those indicators and soil enzemes' activity.The result shows that:1?Soil pH value and EC were the highest in HG area,TS,TC,SOC,AP and AK with the increase of stocking rates were decreased,while TN and AN increased at first,then decreased,and then increased.Soil C:N was the lowest in HG area.AGB and BGB decreased with the increase of stocking rates,and R/S was the highest in HG area.Except for EC,TN and AN were different between soil layers of LG area and HG area,others were different between soil layers in every stocking rates area,and they were manifested as0-10 cm>10-20 cm.2?With the increase of stocking rates,Dehydrogenase,?-glucosidase and phosphatase's activity were decreased,urease's activity were increased at first and then decreased,and then increased.The activities of Dehydrogenase and Urease in soil layers were significantly different in soil layers at higher stocking rates area(MG and HG),?-glucosidase was significantly different in soil layers at lower stocking rates area(CK and LG),there were significant differences of Phosphatase's activity in soil layers under different stocking rates,manifested as 0-10 cm>10-20 cm.3?There was a positive correlation between Dehydrogenase and AGB,BGB,TS,SOC,AP and AK.A negative correlation between ?-glucosidase and pH value,a positive correlation between ?-glucosidase and other indexes.Urease was positively correlated with pH,EC,TN,TC,AN and AP.Phosphatase was positively correlated with AGB,EC,TC,TN,AN and AP.Dehydrogenase was significantly correlated with?-glucosidase and Phosphatase,Dehydrogenase was negatively correlated with Urease,?-glucosidase was significantly correlated with Urease and Phosphatase activity.There was a great correlation-ship between Urease and Phosphatase.