Estimation Of Soil Nutrients Loss By Wind Erosion In The Agro-pastoral Ecotone Of Northern China

Soil wind erosion is one of the main processes of soil degradation in arid and semi-arid areas.Scientific evaluation is one of soil wind erosion is an important means of quantitative analysis of soil degradation.The land area affected by wind erosion in China accounts for more than 1/2 of the total area.Wind erosion leads to soil nutrient loss and soil degradation by destroying and stripping nutrient rich topsoil.In this study,The Agro-Pastoral Ecotone of northern China（APEC）was selected as the research area,and the integrated wind erosion model system（IWENS model）and Zender dust emission model were used to simulate the wind erosion dust transport process from 2000 to 2012.The results were used to quantitatively analyze the potential wind erosion modulus and PM₁₀emissions in the APEC,as well as the loss of soil nutrients organic carbon（SOC）,total phosphorus（TP）and total nitrogen（TN）under the erosion of wind,and then the wind erosion and soil fertility changes in the APEC under the erosion of wind were evaluated.The main results are:（1）By comparing the simulation results of the model with the actual wind erosion amount and PM₁₀emission concentration.It is found that there is a significant correlation between the simulation results of the model and the actual wind erosion and PM₁₀emission,which indicates that the IWEMS model and the Zender dust emission model can objectively simulate the soil wind erosion and PM₁₀emission in the APEC.The simulation results reflect the potential of soil wind erosion in the APEC to a certain extent.（2）The temporal and spatial distribution trend of potential wind erosion modulus and PM₁₀release in the APEC is basically consistent:the annual distribution of potential wind erosion modulus and PM₁₀emission in the study area showed an overall decreasing trend from 2000 to 2012;Hunshandake Sandy Land,Horqin Sandy Land and Mu Us Sandy Land are the main hot spots of soil wind erosion and soil dust emission,while soil wind erosion in other areas is mostly mild erosion.In addition,PM₁₀emission values in some dotted and zonal areas（Yanchi in Ningxia,Datong in Shanxi,Zhangjiakou in Hebei and Zhangwu in Liaoning）are also relatively high.（3）Wind speed,vegetation coverage and soil moisture are all important factors affecting the potential wind erosion in the study area.Wind speed is the main driving factor causing soil wind erosion in this area.Vegetation coverage and soil moisture are negatively correlated with soil wind erosion modulus.The leading factors affecting soil wind erosion sensitivity are slightly different in different regions.Increasing surface vegetation coverage and conserving soil moisture can effectively increase surface erosion resistance.（4）The annual average loss of SOC,TP and TN in the surface layer（0-30cm）of the APEC ranged from 0-37.56 g·m^-2·a^-1,0-4.50 g·m^-2·a^-1and 0-3.27 g·m^-2·a^-1,respectively,and The annual average loss of SOC,TP and TN is about 0.018 g·m^-2·a^-1,0.21 g·m^-2·a^-1,0.019 g·m^-2·a^-1,respectively.From 2000 to 2012,the loss of various nutrients caused by wind erosion showed a significant downward trend.The serious soil nutrient loss areas in the APEC are mainly concentrated in the three sandy lands and the farmland and grassland near the sandy land.The soil nutrient loss in farmland is the most serious,followed by grassland and sandy land.For different land use types,soil nutrients in farmland and sandy land were mainly SOC and TP loss,while those in grassland were mainly SOC and TN loss.The reason may be that different physical and chemical properties of different land use types lead to uneven soil nutrient content,which further affects the loss of soil nutrients to varying degrees.This paper studies the wind erosion of surface soil and the loss of soil nutrients under the action of wind in the APEC,And evaluate the characteristics of soil nutrient loss of different land use types.The research results are helpful to deeply understand the mechanism of land degradation in the APEC and provide scientific basis for regional agricultural development and ecological environment restoration.