乌兰布和沙漠东北缘5种土地利用类型土壤粒度特征

研究荒漠化发生区域的土壤粒度特征,可为区域荒漠化防治及生态建设提供一定理论依据。通过野外调查、采样及室内分析,对乌兰布和沙漠东北缘5种不同土地利用类型(流动沙丘、草方格沙障固沙区、人工梭梭林、白刺群落和油蒿群落)的土壤粒度特征及分形维数进行了研究。结果表明:(1)5个样地土壤颗粒组成均以细沙为主,含量为66.49%~81.54%;粉沙含量最少,仅为0.58%~1.72%;不同粒级土壤颗粒百分含量由高到低为:细沙中沙极细沙粗沙粉沙。(2)5个样地土壤颗粒分形维数的差异极显著(p0.01),油蒿群落(1.72)白刺群落(1.56)人工梭梭林(1.44)流动沙丘(1.40)草方格沙障(1.37);土壤颗粒分形维数与粉沙、极细沙百分含量呈极显著正相关(p0.01),与细沙百分含量呈显著负相关(p0.05),与中沙和粗沙百分含量关系不显著(p0.05)。(3)天然植被生长区域,植被盖度较好,风沙土颗粒较细。因此,应加大对区域内天然植被的保护,防止土壤风蚀的发生与发展。

Soil Grain Size Characteristics of Five Land Use Types in the Northeastern Margin of Ulan Buh Desert

Study of soil particle size characteristics in desertification area can provide certain theory basis for the regional desertification control and ecological construction.Study on soil grain size characteristics in five different land use types (mobile sand dunes,grass square barrier,Haloxylon ammodendron,Nitraria tangutorum community,Artemisia ordosica community) and fractal dimension in the northeastern margin of Ulan Buh Desert through the field sampling and laboratory experiments was carried out.The results showed that:(1) the content of fine sand was greater than else size fraction sand in the pilot site which was fluctua ted between 66.49％～81.54％,and the content of fine sand was the lowest in the five sample plots(0.58％ ～1.72％).The contents of different size particles decreased in the order:fine sand＞middle sand＞mighty fine sand＞coarse sand＞silt sand;(2) the fractal dimensions of five sampling plots were significantly different (p＜0.01),and the fractal dimensions decreased in the order:Artemisia ordosica community sample area (1.72) ＞ Nitraria tangutorum community sample area(1.56)＞Haloxylon ammodendron sample area(1.44)＞mobile sand dunes(1.40)＞grass square barrier(1.37);the fractal dimension was positively correlated with the percentages of silt sand and mighty fine sand (p＜0.01),was negatively correlated with percentage of fine sand (p＜0.05),was not significantly correlated with percentage of middle sand and coarse sand (p＞0.05);(3) The areas growing natural vegetation are characterized as the good vegetation coverage and soil granule is finer,as a result,we should increase the protection of natural vegetation in order to prevent the occurrence and development of the soil wind erosion in this area.