Study On Protection Benefits Of Sand Barrier In Grassland Mining Area

Sand barrier is one of the important measures to slow down wind erosion and promote vegetation restoration and soil improvement.In this study,different reed curtains sand barrier and Salix psammophila sand barrier are set on the slope of the dump in the grassland mining area as the research object.Field investigation and laboratory test methods are adopted to investigate the wind speed,soil and vegetation in the sand barriers,and explore the effect of different sand barriers on ecological protection in the study area,so as to provide theoretical basis and data support for the ecological restoration of the dump in the grassland mining area.The main research results are as follows:(1)The sand barrier can reduce the surface wind speed,and the size and height of the sand barrier have a great influence on the windproof effect.The windproof efficiency of the sand barriers tended to decrease as the observation height increased.At an observation height of 10 cm,the windproof efficiency of the sand barriers was most pronounced,with an average wind protection effectiveness of 50.03%.As the wind speed gradient increased,the windproof efficiency also tended to increase.In terms of size,the windproof efficiency of both materials was 0.5 m×0.5 m > 1.0 m×1.0 m > 1.5 m×1.5m.In terms of barrier height,the average wind protection effectiveness of the 30 cm Salix psammophila sand barriers increased by 26.93% compared to the 10 cm Salix psammophila sand barriers.(2)The trends of aerodynamic roughness and frictional wind speed with sand barriers are generally consistent with the windproof efficiency.The wind speed profiles within the sand barriers show an irregular "S" shaped curve.The 30 cm willow barricade reduced the wind speed in the 0-30 cm observation height significantly.The 30 cm Salix psammophila sand barrier significantly reduced the wind speed at the 0-30 cm observation height.In contrast,the 10 cm Salix psammophila sand barrier only reduced the wind speed at the observation height of 10 cm,and to a lesser extent at other heights.(3)The composition of surface soil particles in the reed curtains sand barriers and Salix psammophila sand barriers were mainly silt and very fine sand,and the content of soil particles decreases with the increase of sand barrier size.The contents of soil water content,organic matter,total nitrogen and total phosphorus in the sand barrier were 0.5 m×0.5 m > 1.0 m×1.0 m > 1.5 m×1.5 m,while the p H value and total phosphorus content of soil had no obvious change with the change of sand barrier size.The percentage of 0-250 μ m particles,water content,organic matter,total nitrogen,total phosphorus and total potassium contents in the 30 cm sand barrier were higher than those in the 10 cm sand barrier,and the soil p H value showed that the 30 cm sand barrier was lower than 10 cm sand barrier.(4)The placement of sand barriers promoted herbaceous plant settlement.After one year of restoration,there were 17 plant species belonging to 8 families and 13 genera in the sand barrier plots,and 4 families,4 genera and 6 species in the control plots without sand barriers,with a more homogeneous species composition.The number of plant species within both the reed curtains sand barriers and Salix psammophila sand barriers increased as the size of the sand barrier decreased.The number of vegetation species,diversity and evenness were less influenced by the material of the sand barrier,while the height of the sand barrier had a greater influence on the number of vegetation species and diversity,with the number of vegetation species and diversity index of the 30 cm height Salix psammophila sand barrier being greater than that of the 10 cm height Salix psammophila sand barrier.