不同生态修复措施下水库水源涵养区土壤粒径分布的分形特征

研究了桃林口水库水源涵养区不同生态修复措施下的土壤粒径分布的分形特征及其与土壤容重、有机质含量、孔隙度的相关关系.结果表明:(1)不同生态修复措施下土壤的粒径分布、分形特征不同,其分形维数在2.709 9～2.778 4之间,由大到小顺次为:荒坡封育型>荒坡造林型>疏林补植型>有林地封禁型(人工林)>缓坡梯田封育型>有林地封禁型(天然次生林)>陡坡梯田封禁型.(2)分形维数与不同粒级含量的相关性具有明显差异.分形维数与粘粒成极显著正相关,与3～0.005 mm粒径含量成负相关,与0.005～0.001 mm粒径含量成正相关,与<0.001 mm粒径含量成极显著正相关.(3)分形维数与土壤容重成显著正相关,与有机质含量成显著负相关.与非毛管孔隙度和总孔隙度成极显著负相关,而与毛管孔隙度的相关性不明显.

Fractal Features of Soil Particle Size Distribution on Water Source Conservation Areas under Different Measures of Ecological Restoration

Based on the soil fractal theory and method, this paper studied the fractal features of soil particles size distribution and the relationships between soil fractal dimensions and physical-chemical properties including soil bulk density, organic matter content and porosities under different measures of ecological restoration on water source conservation areas of Taolinkou reservoir. The study can provide reference for the scientific evaluation of forest soil structures, and the reasonable selections and allocation models of ecological restoration measures on water source conservation areas of the reservoirs during ecological restoration. The results indicate that:(l) The soil particle size distributions and fractal features are different under different measures of ecological restoration,and the fractal dimensions range from 2. 709 9 to 2. 778 4. The fractal dimension of soil particle size distribution of barren slope exclusion measures is highest, followed by barren slope afforestation, open forest replanting, forest land closing measures(plantations), gentle slope terrace exclusion measures, forest land closing measures (natural secondary forests), steep slope exclusion measures. (2) There is a significant difference between fractal dimension and grain contents. The correlation is extremely significantly positive between fractal dimension and clay;and the correlation is negative between fractal dimension and soil particle size ranged from 3 mm to 0. 005 mm;but positive between fractal dimension and soil particle size ranged from 0. 005 mm to 0. 001 mm;especially, extremely significantly positive between fractal dimension and soil particle size ranged from 0. 001 mm to 0 mm. (3) There exists a significant positive correlation between fractal dimension and soil bulk density;but significant negative correlation between fractal dimension and organic matter content;especially,extremely significantly negative correlation between fractal dimension and non-capillary porosity and total porosity;while the correlation is not obvious between fractal dimension and capillary porosity.