Soil Wind Erosion Characteristics Study Of Hilly Farmland With Gentle Slope In Bashang, Hebei

Bashang of Hebei Province is the priority areas of the soil wind erosion study. For theserious soil erosion problems of this areas, Many scholars used different methods of windtunnel experiments and field observations experiments.They did a large number of detailedresearch of the history of development and current situation of the soil erosion problem,occurrence mechanism and constraints solutions and achieved fruitful research results. As weall know, the most prominent of the soil erosion problem in the district is the farmland soilerosion.So many scholars took flat farmland as the research object of soil wind erosion. Butthere are a large number of gentle slope hilly areas which accounted for57.7%of the totalland area in the north and east of Kangbao County in the Bashang area. Therefore, the authorwho used the method of field observation and testing researched on the soil wind erosion ofthe hilly farmland with gentle slope in Kangbao County in the Bashang area, which provides atheoretical basis and mitigation for the gentle slope the cultivated soil erosion problem in thestudy area. Through the analysis concludes the research conclusions:(1) In the point (1to12)of the gentle slope of arable land along the north-south aspect,wind speed ratio variation rules of the horizontal direction is that wind speed increased withthe terrain rising in different terrain parts of hilly farmland with gentle slope, mainly due tothe role of micro-topography, the southern slope of the wind speed slightly higher than thenorthern slope.(2) In vertical direction，the height and wind speed showed the variation of thelogarithmic function. North slope surface roughness is greater than the south slope. Themaximum value of surface roughness appeared in eight points.(3) Amounts of soil wind erosion and wind speed showed the variation of theexponential function in a horizontal direction of the hilly farmland with gentle slop. Axis ofsymmetry to the top of the hill, the wind erosion of the north slope and the southern slope wasa symmetrical distribution. The southern slope of wind erosion was slightly larger than thenorth slope.(4) In the vertical direction from the surface0~60cm, comparative results of the amounts of soil wind erosion is that the wind erosion amount increased with height and windspeed in the height of0~6cm in the middle and bases of slope and0~8cm in the top of theslope. Wind erosion quantity with height increase showed the law of a negative exponentialfunction in the height of8~60cm. When the height was bigger than6cm and smaller than the20cm, lapse rates was greater. When the height was more than20cm, lapse rates wassmaller.(5) In the bottom of north and south slope and middle position of north and south slope,the fine sand content whose size is0.1-0.2mm is the most. In the top of slope, gravel contentwhose soil particle size is bigger than2mm is the most, which accounted for34.28%. In thebottom of north slope、middle position of north and south slope and top of slope, soil particlesize of silt and clay whose size is less than0.048mm is the least. In the bottom of south slope,coarse sand content whose size is between0.5mm and0.6mm is the least which accounted for0.76%.(6) In five different terrain parts of the gentle slope farmland, the peak of soil particlesize which is more than2mm and between0.6mm and0.71mm appears at the top of the slope.The content which soil particle size is more than0.048mm, between0.048mm and0.08mm,between0.4mm and0.5mm and between0.71mm and0.8mm is basic consistent in the fiveposition. The rest of the graded range of particle size change trend are present the followingrules. The least is at the top of the hill. Axis of symmetry to the top of the hill, the curve of thenorth slope and the southern slope was a symmetrical distribution.(7)At the top of the hill, gravel concentration is the most. In the other four position thesoil particle composition is in accord. Sand content is peak value and silt and clay content isvalley value.(8) Surface soil moisture content size order is the bottom of south slope> the top of thethe hill> the bottom of north slope> middle position of north slope> middle position of southslope. Surface soil moisture content maximum which accounted for3.29%appeared in thebottom of south slope. It is1.24times of the top of the slope,1.34times of the bottom ofnorth slope,1.36times of middle position of north slope and1.4times of middle position ofsouth slope. (9) The size of the soil organic matter content is middle position of south slope> bottomof south slope> the top of the hill> middle position of north slope> bottom of north slope.Axis of symmetry to the top of the hill, the soil ph value of the north slope and the southernslope was a symmetrical distribution. bottom of south slope is bigger than bottom of northslope. Soil available potassium> soil alkali-hydrolyzable nitrogen> available soil phosphorus.The change of soil available potassium is the largest amount, soil alkali-hydrolyzable nitrogenis the second smallest and available soil phosphorus. is the smallest.(10) Soil hardness change rule is that the top of the hill is the largest, the difference ofnorth and south slope is not big and middle position of the slope> bottom of the slope.