基于破损规律及植物保存率的沙障选择

机械沙障通过增大地表粗糙度,将近地表风速降至起沙风速以下,从而有效控制沙面颗粒移动,是流动沙区植被恢复前期的重要措施,研究沙障的保存情况对提高机械沙障的治沙效率有重要作用。以铺设在吉兰泰盐湖东北侧流动沙丘上的4种不同规格（0.5 m×0.5 m、1.0 m×1.0 m、1.5 m×1.5 m、2.0 m×2.0 m）的生物可降解聚乳酸纤维（PLA）沙障、麦草沙障为研究对象,对其布设1个风季后沙障破损情况及障内植物保存率进行调查分析。结果表明:1）1.5 m×1.5 m规格机械沙障的破损率在4种规格中较低,其中PLA沙障在背风坡坡中、坡顶的总破损率分别为87.5%、60.71%,麦草沙障为40.28%、83.33%;2）PLA沙障在背风坡坡中破损以全埋为主,在0.5 m×0.5 m规格达到100%,麦草沙障在坡顶破损程度较大,在2.0 m×2.0 m规格达到100%;3）2年生梭梭在1.0 m×1.0 m规格机械沙障内的保存率较高。结合当地实际情况,在布设机械沙障时,选择1.0 m×1.0 m或1.5 m×1.5 m规格的PLA沙障为宜。

Sand Barrier Selection Based on the Damage Rule and Plant Preservation Rate

By increasing the surface roughness,the mechanical sand barrier reduces the near-surface wind speed below the threshold of sand removing,thereby effectively controlling the movement of sand surface particles.It is an important measure in the early stage of vegetation restoration in mobile sand areas.Researches on the preservation of sand barriers can improve the efficiency of the sand control by mechanical measures.In this paper,degradable polylactic acid fiber (PLA) and wheat straw were used as materials to set up mechanical sand barriers with four sizes (0.5 m×0.5 m,1.0 m×1.0 m,1.5 m×1.5 m,and 2.0 m×2.0 m) on the mobile dunes in the northeast side of Jilantai Salt Lake.The damages of the barriers and the preservation rate of the plants within the barriers after a winding season were investigated and analyzed.The results show that 1) the damage rate of the 1.5 m×1.5 m mechanical sand barrier was the lowest among the four sizes,and the total damage rate of the PLA sand barrier in the leeward slope and the top of the slope were 87.5% and 60.71% respectively,they were 40.28%,83.33% for the wheat straw sand barrier.2) PLA sand barriers were mostly fully buried in the leeward slope,reaching 100% in the 0.5 m×0.5 m size,and the wheat straw sand barrier was damaged at the top of the slope,reach 100% in the 2.0 m×2.0 m size.3) The preservation rate of the 2-year-old Haloxylon ammodendron in the 1.0 m×1.0 m size was relatively high.In consideration of local actual conditions,when laying mechanical sand barriers,it was recommended to choose PLA sand barriers with the size of 1.0 m×1.0 m or 1.5 m×1.5 m.