Test And Evaluation On Influences Of Vegetation Coverage On Soil Wind Erosion By Means Of The Movable Wind Tunnel

Soil wind erosion is the most important problem to the sustaining development of agriculture. It is urgent to improve ecological environment. Since new China founded, many progress have been made on building the ecological environment and vegetation. However, the vegetation coverage's influence on soil wind erosion is still paid little attention and need to do the research of their principle in the actual regions.At present, the research of vegetation's influence on soil wind erosion are mostly completed by observation outdoors or simulation indoors. But the both solutions have its limitation respectively. The movable wind erosion tunnel which can simulate all kinds of nature winds is employed to test some parameters of soil wind erosion. Its spot measurements are real absolutely and it can overcome some shortcomings of outdoor observation and indoor test efficiently.In this paper, we select several vegetation coverage lands and measure them by means of the movable wind erosion tunnel produced by Inner Mongolia Agricultural University in the experimental area of Wuchuan county and Zhaohe's grassland of Inner Mongolia on the basis of studying the relative literatures at abroad and home. The measure and evaluation are carried out on aerodynamics characteristic parameters of different vegetation coverage lands and amount of wind erosion. The results are listed as follows. Aerodynamic roughness and shear velocity increase with the vegetation coverage increasing, and further aerodynamic roughness increases according to three cubed curve under the condition of the same wind velocity. The amount of soil wind erosion decreases exponentially with vegetation coverage increasing in the case of different wind velocity. When vegetation coverage is constant, the amount of soil wind erosion increases exponentially with wind velocity increasing. The amount of anti-wind erosion is conspicuous as its vegetation coverage is above 30%. The measured area's effective vegetation coverage is determined as follows. It has to come up to above 40% when wind velocity comes to 10m·s-1 and it must come up to 60~80% when wind velocity comes to 14~18m·s-1. Whirl Type Separation Sand Sampler's calibration coefficient is measured as 5.08‰by the calibration experiment. Moreover, the calibration coefficient does not vary with soil sample,the central velocity of the wind tunnel and the time of collection changing. It has a good stability. All studies can offer scientific evidence on theory and practice for anti-wind erosion work in these regions and agricultural production.