Studies On Effect Of Stocking Rate On Soil Health On Desert Steppe

Soil health is a combination of physical,chemical and biological properties of the soil,and an important basis for the ecosystem to provide various services.Desert grasslands are widely distributed in China and mostly located in areas with arid climate and poor soil,and their resistance to disturbance is relatively weak,so they are also considered to be one of the most sensitive ecosystems to climate change and perceived disturbance.In recent years,unreasonable grazing measures have led to serious damage to desert grassland ecosystems and extensive degradation of vegetation and soils.There are relatively few studies on the effects of grazing on soil health in desert grasslands.In this study,based on the long-term grazing test platform of desert grassland in Siziwang Banner,Inner Mongolia,28 soil physical,chemical and biological indicators were measured by field sampling combined with indoor analysis to analyze the effect of livestock loading rate on soil indicators and assess the soil health condition of different livestock loading rates.It aims to provide theoretical basis for ecological restoration of desert grasslands and formulation of reasonable grazing management measures,which are important for improving vegetation degradation of desert grasslands and ensuring normal development of animal husbandry.The main results are as follows.(1)The above-ground biomass and density of light grazing were not significantly different from the control grassland(P>0.05),plant cover,Simpson index and Shannon-wiener index increased significantly(P<0.05),while the above-ground biomass and cover of moderate grazing and heavy grazing decreased significantly(P<0.05)and density increased(P<0.05).(2)Light grazing soil porosity and saturated hydraulic conductivity were significantly higher than other treatments(P<0.05),soil bulk weight and microaggregates were significantly increased(P<0.05),and field water holding capacity and agglomeration stability were significantly decreased(P<0.05).The ammonium and nitrate nitrogen contents of lightly grazed soils were significantly lower(P<0.05)than those of control grassland.Moderate grazing significantly increased soil pH but significantly decreased soil organic matter content(P<0.05).Total N was significantly higher in heavily grazed than control(P<0.05).Total phosphorus and effective phosphorus under grazing were not significantly different from natural grassland(P>0.05).Soil active carbon content was highest under light grazing(P>0.05)and decreased significantly with increasing stock loading rate(P>0.05),and the trend of microbial quantity carbon content was similar to that of active carbon.Microbial extracellular enzyme activity decreased significantly(P<0.05)with the increase of stock loading rate.(3)The soil health index was lower than that of the control grassland at different loading rates,and the soil health index of the grassland decreased significantly(P<0.05)with increasing loading rate,and the difference between different loading rates was significant(P<0.05).Soil biological properties were better correlated with soil health and were more sensitive indicators of soil health.