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通过野外调查取样和室内分析的方法研究了准噶尔盆地南缘绿洲-沙漠过渡带不同地段的梭梭灌丛土壤不同空间位置(包括灌丛下和灌丛间)的土壤颗粒分形维数的变异特征,以及分形维数与土壤机械组成、土壤养分的关系。结果表明:①土壤颗粒分形维数与土壤沙粒含量呈极显著负相关(P<0.01),与土壤粉粒和粘粒含量呈极显著正相关(P<0.01),并与土壤养分含量中的有机质、全氮、全磷呈极显著的正相关(P<0.01),与可被植物吸收利用的速效形态养分碱解氮、速效钾、速效磷等的含量有极显著的正相关关系(P<0.01),土壤颗粒分形维数可用以表征土壤结构性状和肥力特征。②沙漠-绿洲过渡带典型空间位置的土壤粒级分布呈梯度性变化,从绿洲到沙漠1~0.25 mm的土壤颗粒体积百分比从0.4%增加到16%,而小于0.05 mm的颗粒体积百分比从76.6%减少到3.5%,土壤的粗粒组分明显增加,细粒组分明显递减,并且土壤颗粒分形维数从2.50降低到2.03。③不同粒径土粒的分布规律表现为灌丛下的粉粒、粘粒含量均大于灌丛间的,其中沙漠腹地灌丛下的表层土壤粉粒增加了1.23%,粘粒增加了0.06%;退耕还林地灌丛下土壤表层的粉粒增加了10.78%,粘粒增加了2.91%,说明梭梭灌丛能有效截获风蚀带来的微细尘埃、粘粒和粉沙,使灌丛下土壤的结构及肥力性状得以改善,形成灌丛“肥岛”。
Through field survey and sampling and laboratory analysis, the variation characteristics of soil particle fractal dimension in different spatial locations (including shrubs and shrubs) of Haloxylon ammodendron shrub soil were studied in different parts of the oasis-desert transitional zone in the southern margin of Junggar Basin , As well as the relationship between fractal dimension and soil mechanical composition and soil nutrient. The results showed that: (1) There was a significant negative correlation between soil fractal dimension and soil sand content (P <0.01), and significant positive correlation with soil silt and clay content (P <0.01) (P <0.01). There was a significant positive correlation between content of available nitrogen, available potassium and available phosphorus in the available forms that could be absorbed and utilized by plants ( P <0.01). The fractal dimension of soil particles can be used to characterize soil structure and fertility. (2) The soil particle size distribution in the desert-oasis transitional zone showed a gradient change from 0.4% to 16% from the oasis to the desert, while the percentage of the particles with the volume less than 0.05 mm increased from 76.6% % To 3.5%. The content of soil coarse grains increased obviously, the fraction of fine grains decreased obviously, and the fractal dimension of soil grains decreased from 2.50 to 2.03. The distribution of soil particles with different particle size showed that the content of silt and clay in the shrubs were all larger than those in the shrubs. The surface soil silt in the desert hinterland shrubs increased by 1.23% and the clay particles increased by 0.06% The grain size of soil surface increased by 10.78% and the clay content increased by 2.91% under the shrub land of returning farmland to forestland, indicating that Haloxylon ammodendron shrub could effectively intercept the fine dust, clay and silt caused by wind erosion, The structure and fertility traits can be improved, forming scrub “fat island ”.