Design of wind-break walls and their application in Hulunbeier sandy land control

The grassland desertification is serious in Hulun Lake Basin. 5 different heights and hole types of movable wind-break walls (Ⅰ:2.0 m high, stripe-shaped holes, Ⅱ:1.5 m high, stripe-shaped holes, Ⅲ:1.0 m high, stripe-shaped holes, Ⅳ:1.0 m high, square holes, Ⅴ:1.0 m high, circular holes) were developed and designed as sand barriers in order to explore the ecological restoration modes in serious desertification patches. The windbreak effects of wind-break walls were compared and the characteristics of wind speed at different distances and heights from the surface and surface soil moisture content behind them were determined, which could provide references for the installation of wind-break walls in areas with frequent winds. The results showed that, all wind-break walls could reduce the wind speed within limit distance and the windbreak effect at 0.5 m from the surface were higher than that at 1.0 m. At the distance of 1 m behind the wind-break walls and the height of 0.5 m from the surface, the windbreak effects were Ⅴ(87.30%)>Ⅰ(83.91%)>Ⅱ(83.29%)>Ⅳ(80.20%)>Ⅲ(74.66%). The order of water holding capacity of surface soil was Ⅴ>Ⅰ>Ⅱ>Ⅳ>Ⅲ and the cost of them was Ⅰ>Ⅱ>Ⅴ>Ⅳ>Ⅲ. Therefore, the structural parameters of the wind-break walls that were more suitable for Hulun Lake Basin were as follows: 1.5 m high, stripe-shaped holes; 1.0 m high, circular holes.