民勤荒漠-绿洲过渡带不同沙障的阻沙粒度分析

Comparative Analysis of Grain Size of Different Sand Barriers in Desert-Oasis Ecotone in Shajingzi Area of Minqin County

对民勤沙井子地区荒漠-绿洲过渡带的尼龙网格沙障、白刺沙障和沙拐枣沙障阻截的沙物质进行采样,运用沉积物的粒度分析方法,以流动沙丘和丘间地沉积物为参照,对比分析了研究区内不同沙障所拦截的沙物质的粒度组分及参数特征.结果表明：两种植物沙障拦截的沙物质粒度特征较为相似,拦截的沙物质均以细砂和极细砂为主,对容易形成风沙危害的粒径区间（1.32～4Φ）的拦截量均可达90%以上,而尼龙网格沙障拦截的沙物质相对较粗,对1.32～4Φ区间的拦截量为70%.从阻沙粒度特征上看,植物沙障的阻沙效果明显要好于尼龙网格沙障.此外,在〉2Φ的粒径范围内,两种植物沙障拦截的沙物质主要来源于丘间地,尼龙网格沙障拦截的沙物质主要来源于流动沙丘.

Samples were collected from the sand intercepted by different sand barriers including nylon net sand barriers,nitratia tangutorum sand barriers and Calligonum junceum sand barriers in the area of Shajingzi in Minqin.Analyzing the grain size of sediments and compared with the mobile dunes and interdune sediments,this paper discussed the features of grain size of sediments intercepted by different sand barriers.Results showed that the features of grain size of sand intercepted by two plant sand barriers were similar.They mainly intercepted fine sand and very fine sand and could intercept 90% of the sand（1.32 ～4Φ）that could lead to sandstorm.The sand intercepted by nylon net sand barriers intercepting 70% of the sand（1.32～4Φ）tended to be coarser.In terms of the features of grain size of the intercepted sand,plant barriers were more effective than nylon net sand barriers.In addition,the sand intercepted by plant sand barriers mainly came from interdune lands,while the sand intercepted by nylon net sand barriers was mainly from mobile dunes.