The Research On Granularity Characteristics Of The Surface Soil And Erodibility Particle In The Desertification Land In Inner Mongolia

Abstract: The Blown Sand-dust on surface soil and soil degeneration are the primary environmental problems in Inner Mongolia by the wind erosion and desertification. The occurrence and development of wind erosion has close connection with physical and chemical characteristics on the surface soil. This paper studied on the sand land or desert in Inner Mongolia, by field practical location, field investigation and sampling, combined with experimental analysis in room. It researched granularity characters of surface soil in different land types and space variation on the sandlot or desert in Inner Mongolia. At the same time, it combined the research on wind tunnel about the erosive particles and the experience from the former scholars to analyze the potential distribution about the surface soil erosive particles on the sand land or desert in Inner Mongolia. In order to study the movement of the wind-sand flow, discuss the deposit environment and provide theoretical support to transform the sandy land.The conclusions are as follows by the research:(1) Grain-size parameter value shows multi-solutions character for the different step length of grain-size subsection leads to different. As a whole, it has a negative correlation between the situation of dispersion of grain-size parameter and the number of subsection. The amount of the number of subsection is the main factor that affects the result of moment calculating.(2) As for the variation of surface soil granularity in different land type, it shows that: there are connatural rule in the other five places, except that the differentiation of the characteristic of mobile dune in the sand land of Hunshandake is not obvious. That is, the mobile dune is thicker than the other dunes, the distribution is good and the peak value is big. Next are half-immobile dune, immobile dune and degenerative infield. The non-degenerative infield, the grassland and woodland are thinner than the other places, distribution is bad and the peak value is calm. The surface soil granularity in different land type is mainly fasten on 1-0.05mm and the content is from 41.22% to 98.23%. the granularity in 1-0.05mm is mainly fasten on 0.25-0.05mm and the content is from 25.39% to 94.89%. The content of the silt particle granularity and the clay particle granularity is small in all kinds of land use, especially the mobile dune. It has not the silt particle granularity basically and the content of clay particle granularity is the least.(3) As for the differentiation of surface soil in the typical physiognomy position, the distribution of surface soil granularity variance in different physiognomy position of immobile dune in Keerqin sand land is that the weather slope is thicker than the topmost dune and the bottom dune. The intensity of wind erosion on the topmost of half-immobile dune and mobile dune is much stronger than the dune slope and the bottom dune, which are in leeward slope. The distribution of surface soil granularity variance in different land use in Hunshandake sand land is that the surface of wind erosion bed surface or crevasse surface layer is roughen; the distribution of granularity moves onwards; the content of silt particle grade and clay particle grade is low or do not conclude. The granularity variance in the topmost and bottom of immobile dune is not differentiated basically. As for the surface soil variance of typical land use state, in Keerqin sand land is that the surface soil granularity in corn field of traditional cultivation area is thinner than that in returning cropland to protective land. The content of silt particle granularity and the clay particle granularity is nearly 0 in the sand slope land. The distribution of grain grade is comparatively average in Meadow land and the content of the silt particle grade (0.05-0.075mm)and the clay particle grade (<0.002mm) is comparatively big. The granularity distribution of hermetical grassland is coarse as a whole. It is a truth that the resuming hermetical grassland had ever been wind eroded intensively.(4) As for the special variance of the surface soil granularity in desertification land, the distributing of granularity in the layer of surface soil has obvious rule of spacial variance in Maowusu sand land and Wulanbuhe desert. That is, the grain is coarse in the north and west; it is thin in east and south. The surface soil granularity in the west is coarser than that in the east in Kubuqi desert.(5) As for the surface soil erodibility particles in different land type,the thin grain in all kinds of dune released a lot. That in woodland, infield and grassland released a little. Because the natural condition, the time of activated sampling and the intensity of artificial influence were different, the exhibition had difference. The content of blown dust particles is big in infield and zonality grassland; the content of that in the other dunes is small. Therefore, the dust source particles in the large-scale dust storm mostly come from degenerative infield and grassland.