Studies On Protective Effects Of Shelter Belt Of Highway In Otindag Sandy Land

In wilting period of vegetation, windproof effect, sediment discharge, shrubs trapping sand effect and soil physical properties of shelter belt on both the sides of provincial highway were measured and studied with vegetation bionomics, blown sand physics, statistics and so on, several main conclusions were drawn in this paper as follow:(1) Roughness(z0) is significantly increased by the shelter belt. The highest roughness(z0) measured is 21.6cm, lowest is 3.5cm, effectively preventing wind erosion. Plant coverage is pacing factor for influencing roughness(z0), also height and density of plant have significant positive correlation. The shelter belt wind proof effect is obvious, the results showed that, 5-14m/s wilderness wind falls under 5m/s after shelter belt. The higher and more dense vegetation grow, the effect stronger windbreaks show, and increases with the wind velocity. The sediment discharge observation on steep hill of cutting slope shows that there was 63.84g sand in wilderness, only 1.49g sand trapped in community windward edge of the shelter belt, reducing more than 42 times, while 0g sand trapped in community middle and leeward edge.(2) Shrubs can effectively fix sand and different kinds have different sand trapping capacity. Artemisia intramongolica trap the most sand amount in the three kinds of shrubs, the average achieves 0.033m3. Shrub shape greatly affects its sand trapping capacity, Artemisia intramongolica mainly affectsed by basal diameter and crown diameter, especially basal diameter; salix flavida mainly affectsed by crown diameter. In terms of shrub shape, the bigger"basal diameter"and"crown diameter"is, the more stronger trapping capacity show.(3) The shelter belt enhanced the surface water content, and it had positive correlation with vegetation coverage. Surface soil bulk density significantly less than the lower. Soil bulk density in the shallow soil layer (0-15cm) was weakly less than the control. Coarse and middle sand of shallow soil layer in the relative content larger than bare sand, fine sand slightly reduced, silt and clay double increased.