大黑山生态修复区不同植被类型土壤颗粒的分形特征

运用土壤粒径质量分布原理与分形理论,对大黑山生态修复区6种不同植被类型土壤颗粒分形特征进行研究。结果表明：1）不同植被类型土壤颗粒粒径的质量分数分布差别很大,土壤黏粒和粉粒含量林地比荒草地高87.47%和89.94%,砂粒含量和细砾与粗砾含量林地比荒草地低25.09%和19.19%;土壤粉粒和黏粒含量黑桦＋山杨混交林、蒙古栎和山榆等天然次生林地明显高于山杏和油松等人工林地。2）有林地土壤颗粒分形维数明显大于荒草地,天然次生林土壤颗粒分形维数大于人工林,且以天然次生混交林最大。3）不同植被类型土壤颗粒分形维数与土壤粒径〈0.05 mm的黏粒含量和粒径0.05-0.25 mm之间的粉粒含量呈明显的线性正相关关系,土壤的颗粒越小,细粒含量越高,分形维数越大。4）不同植被类型土壤颗粒分形维数与土壤不均匀系数呈较好的线性负相关关系,随着土壤不均匀系数的降低,土壤颗粒分形维数增大。除荒草地外,大黑山生态修复区其他5种植被类型土壤均为不均匀性良好的土壤,以天然次生林土壤粒径分布结构较好,尤其是以天然次生混交林的最好,其次是人工林的。

Characteristics of soil particles fractal dimension under different forest stands of the ecological restoration area in Dahei Mountain area

In order to evaluate the effect of the ecological restoration on soil structure and function,characteristics of soil particles fractal under 6 typical vegetations of the ecological restoration area in Dahei Mountain area were studied according the quality principle of soil particle size distribution and theories of soil fractal.The results showed that:1)The soil particle size distribution of the different vegetation types varied greatly,the contents of soil clay and silt under woodland were 87.47% and 89.94% higher than that of grassland;sand and fine gravel content and coarse gravel content of woodland are lower 25.09% and 19.19% than that of grassland;in the various forest vegetation types,soil clay and silt content of natural forest such as Betula davurica Pall+Populus davidiana mixed,Quercus mongolicus Fisch and Ulmus macrocarpa are significantly higher than that of artificial forest such as Prunns mandshurica and Pinus tabulaeformis Carr.2)Soil particles fractal dimension of woodland is significantly higher than that of grassland,and natural forest is higher than that of artificial forest,and to the greatest is secondary natural mixed.3)The soil particles fractal dimension of the different vegetation types has a significant linear positive correlation to the clay content of soil particle size <0.05 mm and the silt content of soil particle size 0.05～0.25 mm.The soil particle is smaller,the higher the fine-grained concentration,the greater the fractal dimension.4)The soil particle fractal dimension of the different vegetation types had a significant negative linear correlation with soil uneven coefficient.Along with the lower soil uneven coefficient,fractal dimension of soil particle was increased.In addition to grassland,the other five typical forest stands are good structural soils in soil uneven coefficient.Soil particle distribution of natural forest is better,particularly,the secondary natural mixed the best,artificial forest is next-best.