The Response Of Physico-chemical Property And Soil Microbial To Grazing And Fertilization On Alpine Meadow

The effect of grazing and fertilizing on soil properties are inconsistent because of the complexity hysteretic nature and flexibility of soil system. Water content,pH,organic carbon,total nitrogen,microbial biomass carbon, microbial biomass nitrogen, soil respiration, qCO2were chosen for the soil physico-chemical property and micro biomass effect of different grazing intensity and different fertilizer levels on Tibetan Plateau, the results are as follows:1. The effect of grazing on soil physico-chemical property and micro biomass in alpine meadow.In the year of2011, the different grazing intensity has significant impact on Water content, pH, soil organic carbon, total nitrogen. The tendency of water content were Non-grazing> Full-grazing> Seasonal-grazing, soil organic carbon, total nitrogen and respiration are the highest in non-grazing area. There was a significant positive correlation (P<0.01) between soil respiration and organic carbon, total nitrogen, water content, a significant negative correlation (P<0.01) between total nitrogen and soil moisture, organic carbon, a positive correlation (P<0.05) between organic carbon and soil moisture. In the year of2012, the water content were reduced by the increasing of grazing intensity in different soil depth (O-15,15-30cm) and the tendency were Non-grazing> Seasonal-grazing> Full-grazing;there is no significant difference in the pH value in different soil depth; the microbial biomass were significant effected by different grazing intensity in different soil depth the tendency of the microbial biomass carbon and microbial biomass nitrogen were Seasonal-grazing> Full-grazing> Non-grazing; qCO2was larger under Full-grazing; water content> microbial biomass carbon、microbial biomass nitrogen were0-15cm>15-30cm under the same grazing intensity; qCO2was15-30cm>0-15cm under the same grazing intensity. There was a significant positive correlation(P<0.01)between microbial biomass carbon and soil moisture, microbial biomass nitrogen, a significant negative correlation (P<0.01)between respiratory quotient and soil moisture, microbial biomass carbon, microbial biomass nitrogen, a significant positive correlation(P<0.01)between soil moisture and pH, microbial biomass nitrogen.2. The effect of fertilizing on soil physico-chemical property and micro biomass in alpine meadow.In the year of2011, the different fertilizer levels have significant impact on Water content, pH, microbial biomass carbon at the depth of0-15cm in July. Microbial biomass carbon and respiration decrease with increasing grazing intensity, the microbial biomass nitrogen increases with the increasing grazing intensity. In the year of2012, the different fertilizer levels has significant impact on Water content, pH, microbial biomass carbon, microbial biomass nitrogen at the depth of0-15cm in May, July and September. Microbial biomass carbon, microbial biomass nitrogen and respiration are the highest in the area of (NH4)2HPO4of60g/m2.The microbial biomass carbon and microbial biomass nitrogen increase with the increasing fertilizer levels in the area of (NH4)2HPO4<60g/m2, the microbial biomass carbon and microbial biomass nitrogen decrease with the increasing fertilizer levels in the area of (NH4)2HPO4<60g/m2. In the different sampling time,the change tendency of microbial biomass carbon and microbial biomass nitrogen were May> September> July.