高寒沙区沙障固沙效益与生态功能观测研究

Field Measurements of Sand-barrier Benefits and Ecological Functions in Sandy Lands of Qinghai-Tibet Plateau

采用样地调查法对共和盆地设置的沙障进行连续3 a风积风蚀以及土壤水分观测。结果表明,粘土沙障取材廉价方便,保水、抗风蚀性能强,是适合高寒沙区的较理想的沙障,同时在沙丘坡度4%～12%之间容易形成水蚀沟,最大水蚀沟密度达到14%,破坏沙障的整体稳定性;麦草方格沙障施工简单,防护期较短,由于高寒沙区麦草资源匮乏,推广使用受到限制;近年来小区试验的尼龙网格沙障风蚀沙埋严重,防护效果并不理想。

Sand-barrier is the main engineering measures for vegetation restoration in sand dunes. Various types of sand-barriers play different effective roles in stabilizing sands. So the research on the ecological functions and sand control of sand-barriers has a great importance on the desertifieation controlling. In this paper,based on 3 consecutive years field measurement of erosion, deposition and water content in preventing system at sand control experimental area in Gonghe basion, sand-barrier benefits and ecological functions are discussed. Results show that the clay and gravel barrier has the advantages for its less cost and convenient planting, best fixing-sand capability and water-holding, except its disadvantage of rill and gully erosion on the slope between 4 % - 12 % of sand dunes which reduce the projects stability, the maxim channel density up is to 14%. Wheat or rice straws are convenient for planting the checkerboards and sand barriers while with the shorter survival period and scarce resources in Qinghai-Tibet Plateau. Sand barriers made of nylon nets have been tested in recent years with undesirable results as its weak function to prevent the wind erosion and sand burying.