Spatial Distribution Characteristics And Influencing Factors Of Soil Physical And Chemical Properties In Temperate Desert Of Xinjiang

Soil physical and chemical properties are one of the main factors affecting vegetation growth and soil nutrient content.Desert is the most important ecosystem in arid areas,accounting for 1/4 of the global land area and 27.9% of China’s land area.Among them,the temperate desert is the most typical ecosystem in Xinjiang.The study on the spatial distribution characteristics and influencing factors of soil physical and chemical properties in the temperate desert of Xinjiang is of great significance to the development of animal husbandry and soil and water conservation.Based on the measured soil profile data from 121 temperate desert soils in Xinjiang,the spatial distribution characteristics of soil physical and chemical properties(organic carbon content,inorganic carbon content,p H,bulk density and soil-rock ratio)and their responses to climate,elevation,aboveground net primary productivity,root biomass and other soil physical and chemical properties were analyzed.The main results are as follows:(1)The change of bulk density with soil depth is not obvious.In 0-20 cm soil layer,bulk density was negatively correlated with mean annual temperature and elevation.Soil organic carbon was negatively correlated with soil organic carbon at 0-5 cm and 10-20 cm.There was a negative correlation with inorganic carbon content in 0-30 cm soil layer.At 20-30 cm,it is positively correlated with the ratio of soil to rock.However,the mean annual temperature and p H had no effect on bulk density in the seven soil layers.(2)In 0-30 cm soil layer,the ratio of soil to rock increases with the increase of soil depth,but in30-100 cm soil layer,the ratio of soil to rock decreases with the increase of soil depth.The mean annual precipitation has no effect on the soil-rock ratio.At 0-5 cm,5-10 cm and 70-100 cm,there was a positive correlation with the mean annual temperature.In seven soil layers,it is positively correlated with elevation.Soil organic carbon content,p H and bulk density had no effect on the soil-rock ratio,but the soil-rock ratio increased with the increase of soil inorganic carbon content in 0-50 cm soil layer.(3)Soil organic carbon content decreased with the increase of soil depth,while soil inorganic carbon content increased with the increase of soil depth.At 20-30 cm and 30-50 cm,soil organic and inorganic carbon contents were positively correlated.In 0-30 cm soil layer,soil organic carbon content was positively correlated with mean annual precipitation,aboveground net primary productivity and root biomass,but negatively correlated with bulk density and p H.Among the seven soil layers,the relationship with elevation is unimodal,but has no relationship with the ratio of soil to rock.In the seven soil layers,soil inorganic carbon content had a positive correlation with mean annual temperature,a single-peak relationship with p H,but no relationship with annual precipitation.In 0-20 cm soil layer,there is a positive correlation with elevation,but in 20-100 cm soil layer,there is a single-peak relationship with altitude.In each soil layer of0-30 cm,it is negatively correlated with bulk density.In each soil layer of 0-50 cm,the ratio of soil to rock was positively correlated.(4)pH does not change with soil depth.Average annual precipitation and mean annual temperature had no effect on p H.In 0-50 cm soil layer,p H first decreased and then increased with elevation.At 0-5 cm,there was a negative correlation with aboveground net primary productivity.At 30-50 cm and 70-100 cm,it was positively correlated with root biomass.There was a negative correlation between soil organic carbon content and soil organic carbon content in 0-30 cm soil layer.Soil inorganic carbon,bulk density and soil-rock ratio had no effect on p H.In conclusion,mean annual precipitation,mean annual temperature,elevation,aboveground net primary productivity and root biomass all had different effects on soil physical and chemical properties,and there was a certain relationship between the physical and chemical properties.The results can provide a theoretical basis for sustainable utilization of desert ecosystem and provide some data support for scientific management of temperate desert in Xinjiang.