沙漠矿物组成与生态修复的互馈关系研究

以乌兰布和沙漠和库布齐沙漠为研究区域,在流动沙丘、半固定沙丘和固定沙丘分别采集表层(0～20 cm)、中层(20～40 cm)和底层(40～60 cm)沙样,分析了沙漠不同深度沙样的粒径组成、矿物成分、风化程度及三者之间的关系。针对不同植被覆盖区域进行采样,研究了沙漠生态修复与风化程度、黏性矿物含量之间的关系,揭示了沙漠矿物风化程度与生态修复的互馈关系。结果表明:沙漠表层沙样粒径小于中层和底层沙样,黏性矿物含量高于中层和底层;风化程度越高,黏性矿物含量越高,粒径组成越细。植被盖度与矿物风化程度和黏性矿物含量之间具有良好的关系,植被盖度由4%增加至18%～22%时,黏性矿物含量和风化程度增加速率较快,之后增加速率减小。矿物风化程度随生态修复的时间逐渐增加,对库布齐沙漠来说,随着植被盖度和风化程度增加,黏性矿物中伊利石含量显著增加。

Study on the mutualism between mineral composition and ecological restoration in desert area

Taking Ulanbuh Desert and Kubuqi Desert as the research area,sand samples of 3 different surface depth (the surface layer: 0~20cm; the middle layer: 20~40cm; the bottom layer 40~60cm underground) were collected respectively from the fixed dune, semifixed dune and mobile dune from each dessert to analyze the triadic relation between granulometric composition,mineral constituent and the degree of weathering. The relationship between the weathering level and cohesive mineral content and the desert ecological restoration was studied by sampling in different vegetation coverage area,and the mutualism relationship between the degree of mineral weathering and ecological restoration was revealed. The consequence shows that,the sand grain size in the surface level is smaller than the middle and bottom level;the higher the degree of weathering,the higher the cohesive mineral content and the smaller the grain size. There is a good relationship between the degree of mineral weathering and the cohesive mineral content. Their increase rate rises when the vegetation coverage rises from 4% to 18%~22%,and then the rate falls subsequently. It is a gradual growth of the ecological restoration followed by the degree of mineral weathering. For the Kubuqi Desert,the illite content in the cohesive mineral increased significantly with the growth of weathering and vegetation coverage level.