| Wind erosion has been a major environmental problem, which troubled human survival and development of the environment. This situation were more remarkable in development and construction project area performance in arid region. The measures to enlarge plant cover and set gravel sand barriers could change near-surface sand flow structure and achieve prevention of wind erosion purpose. This paper selected Karabailey Project Area as a study area, and studied its erosion characteristics under different underlying, sand-fixing effect of plants and gravel sand barriers, based on the results from the field measurement and statistical analysis. Main conclusions were as follows:(1)The human disturbance increased the possibility of soil wind erosion and changed the structure of sediment flow in near-surface, which were more obviously shown in repeatedly rolling surface and spoil surface.Compared with the original surface, the sand-blown wind speed of them reduced 2.1 and 2.7 m·s-1 respectively, and erodible soil particles increased 15.7% and 11.6% respectively, the average sand diameter and wind-blown mass also have increased in different degrees at different heights.(2) The main concentration of sand in the project area was centered in 30cm near-surface, the medium sand and its following size particles were primarily wind erosion particles in this aera. The very fine sands and fine sand were the most vulnerable to erosion particles in original surface and disturbanced surface. The wind-blown mass and sand particle size decreased gradually along with the increase of height, and the wind-blown mass decreased exponentially with the hight increment, The decreasing function under original surface, spoil surface and repeatedly rolling surface were:Y= 55.04e-0.150x, Y=30.14e-0.10x, Y=12.21e-0.09x.(3) The main vegetation in project area were Kalidium foliatum, Alhagi sparsifolia, Suaeda maritima. and Anabasis pelliotii, growing in undesirable way. The average area of vegetation coverage, height and density were 4.1%,14.5cm,0.7 plant·m-2, the average prevailing wind direction vegetation crown width was 27.3cm, and perpendicular to the prevailing wind direction average crown width was 28.7cm. There existed a correlation between sand-fixing effect of vegetation, vegetation factor and surface gravel covering, the lower gravel cover degree, the larger plant height, crown width and sand-fixing effect. With the increasing in plant height and crown, the amount of sand increased exponentially. When the plant height and crown were above 15cm and 35cm, sand-fixing is significant, and the impact of plant morphology on sand-fixing amount showed plant height> longitudinal crown> lateral crown.(4) Gravel sand-barrier changed the near-surface spatial distribution of sediment, the amount of sediment discharge after the sand-barrier had biggest differences with the original ground at the height of its sand barrier edge, the degree of difference between them ranged from144.2% to 1880.7%. The higher the sand barrier and the closer to sand-barrier the greater the degree of difference. The comprehensive sand-controlling benefit of sand-barrier decreases with the increase of distance and increase with the increase of the barrier height, the comprehensive sand-controlling benefit of 10cm sand-barrier was weakest, which were both≤15.7% and it could be workde in 80cm after barrier. The comprehensive sand-controlling benefit of 20cm sand-barrier was better than 10cm, which were≥18.7% after sand-barrier 0-120cm, and it could be worked> 120cm. The comprehensive sand-controlling benefit of 30cm sand-barrier were best, which were much better than 10cm and 20cm sand-barrier, it would be worked> 120cm and its comprehensive benefit were both≥47.2%,and 30cm should be optimum hight to set sandy sand-barrier for sand-controlling measures in Carlabailey project area. |
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