Correlation Of Soil Grain Size And Organic Matter In Different Land Types In Mu Us Sandland

The Mu Us Sandy Land is located in the middle of the agro-pastoral ecotone.The ecological environment is fragile and the soil wind erosion is serious.It is one of the key areas for the treatment of desertification in the sand source area of Beijing-Tianjin.This paper provides basic data for the rational use of land and prevention of wind erosion and desertification in Mu Us Sandy Land by studying the soil particle size and organic matter of different land use types.Four land use types of stubble,ploughed land,grassland and semi-fixed dune land are selected on the edge of Mu Us Sandland and collecting soil surface layer（0-5cm）and subsurface layer（5-10cm）experimental samples.The correlation between soil particle size and organic matter was discussed by testing the soil particle size and organic matter content of four soil types in the laboratory.The main conclusions are as follows:（1）There were significant differences in soil organic matter content among the four types of land in the study area.The dominant grains of stubble land,ploughed land and grassland were silt（0.002-0.05mm）,and the silt content of surface soil was grassland（61.06%）> stubble land（53.09%）>ploughed land（48.28%）.The grassland（61.25%）> ploughed land（49.43%）and stubble land（48.42%）were the sub-surface layer.The dominant size of semi-fixed dune is fine sand（0.1-0.25mm）,the surface layer content is52.69%,and the sub-surface layer content is 54.53%.（2）The soil organic matter content of four land types in the study area is significantly different.organic matter is generally grassland(18.75g·kg^-1)>ploughed land(12.53g·kg^-1)> stubble land(11.25g·kg^-1)> semi-fixed dune(8.13g·kg^-1),and the sub-surface layer shows grassland.(13.36g·kg^-1)>Stubble land(13.05g·kg^-1)>ploughed land(12.67g·kg^-1)> Semi-fixed dune land(7.73g·kg^-1).（3）There are significant differences in the K value of soil erodibility indifferent land types.The surface layer（0-5cm）shows the distribution of semi-fixed dune land <tillage land <Stubble land< grassland;The subsurface layer（5-10cm）showed the smallest semi-fixed dune land,and the grassland was the largest.The stubble land and the ploughed land were between the grassland and the semi-fixed sand dune.（4）Correlation analysis of soil granularity and organic matter showed that there was a significant positive correlation between organic matter and silt in stubble land and semi-fixed dune,and a very significant positive correlation between organic matter and medium sand and fine sand in ploughed land.It reflects that the soil organic matter in the ploughed land is unstable and susceptible to other factors.