The Safeguard Of The Farmland Prevent The Sandstorm And The Study On The Model Of The Soil Wind Erosion

The phenomenon of soil wind erosion and desertification has already become the most outstanding problem of agricultural sustainable development of China's north farming-pastoral zone, and is playing an important role in the sandstorm. In recent years, the sandstorm remains high frequency, makes the soil wind erosion receive unanimous attention of the expert of environmental protection of soil.Taking the serious area of soil wind erosion and desertification as a typical region, which lie in the north of Hebei province : Zhangbeu Huailau Fengning, the paper carries on observing and experimental study of wind-tunnel in the field, studies the involved factor which influence the soil wind erosion with the method quantitative analysis, and has set up soil wind erosion models tentatively. The model offers essential theory and technological basis for preventing and curing soil wind erosion. The main research achievements conclude:1. Set up wind erosion trial zone at soil wind erosion and desertification serious areas, Carry on soil wind erosion monitor by the characteristic of local weathers and the plant.The result of the test shows: (1) The wind is the important factor of influencing the soil wind erosion. Under different states of the earth's surface, the value of wind velocity of the closed surface of the earth is different. The functional relation of power exists between the wind velocity and the flux of soil wind erosion. (2) The highest soil granule content concentrate on between 0.045 ~0.25mm in the area taking place wind erosion easily. The remarkable difference exists in different waters content of soil of top layer of state of the earth's surface. The functional relation of power exists between top layer soil water content and flux of soil wind erosion, with the increase of the water content of soil of top layer, the flux of wind erosion of soil is reduced. (3)Different types of the earth's surface vegetations, has different function of reducing wind velocity, sequentially influence the flux of soil wind erosion. It is the important parameters of influencing the soil wind erosion thatthe vegetation covers degree and amount. (4) The highness of the remaining stubble and the earth's surface roughness has functional relation of exponent within the specific limits. If the waters content of soil of top layer is different, the roughness of the earth's surface is different. (5) When main wind directions and the ridge in a field cultivation is perpendicular each other, the flux of soil wind erosion is minimal; while Parallel between them, the soil wind erosion has the largest flux. The treatment of remaining stubble compared with traditional cultivation can reduce the flux of soil wind erosion, and that with the highness of the remaining stubble increasing, the scope of reducing the flux of soil wind erosion ranges in 80. 2%~97. 1%. In controlling soil wind erosion measures, the straw covered is superior to no straw covered in the area that plants grape, the maize straw covered is superior to the wheat straw covered. (6) After the shelter belt of farmland, the change tendency of the wind velocity and the flux of soil wind erosion become lower firsty, and then become great. The windbreak has the function which reduces the wind velocity within the specific limits in of the area that plants grape. When the trend of the windbreak and the direction the main wind are perpendicular each other, the effect of reducing the wind velocity of wind break is the best; Within the specific limits, the effect of the weakening the wind velocity of web of hail-break is obvious .2. Based on analysing in depth to the wind erosion model and field foundation of testing, set up tentatively the soil wind erosion models which is suitable for the study the area.The simulation result of the model and the data of surveying are basically identical, but the verification of the model and appraisal is merely preliminary, still need to verify further.