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基于粒径的重量分布表征分形维数的计算方法,对喀斯特山区植被恢复过程中的土壤颗粒、团聚体、微团聚体粒径分布的分形维数进行研究,并分析其与土壤理化性质的关系。结果表明,随着植被的不断恢复,>0.25mm水稳性团聚体不断增多,土壤结构不断改善;土壤颗粒分形维数除与土壤水解氮呈显著正相关外(P<0.05),与其他因子的相关性较小,均未达显著性水平;土壤微团聚体和水稳性团聚体分形维数与有机质和全氮、水解氮呈显著负相关,与结构体破坏率呈显著正相关。土壤微团聚体及水稳性团聚体分形维数能较好地反映植被恢复过程中土壤理化性质的演变,可以作为定量评价喀斯特植被恢复过程中土壤结构演变的指标;坡耕地的土壤结构最差,退耕还林有利于喀斯特山区水土保持。
Based on the calculation of the fractal dimension based on the particle size distribution, the fractal dimension of the particle size distribution of soil particles, aggregates and microaggregates in the process of vegetation restoration in karst mountains was studied and the relationship between the fractal dimension and soil physico-chemical properties . The results showed that with the continuous restoration of vegetation, the> 0.25mm water stable aggregates increased continuously and the soil structure improved continuously. The fractal dimension of soil particles was significantly and positively correlated with soil hydrolyzable nitrogen (P <0.05) The correlation between fractal dimensions of soil micro-aggregates and water-stable aggregates was negatively correlated with organic matter, total nitrogen and hydrolysable nitrogen, and there was a significant positive correlation between the fractal dimension and the rate of structural damage. The fractal dimension of soil micro-aggregates and water-stable aggregates can better reflect the evolution of soil physicochemical properties during vegetation restoration and can be used as an index to quantitatively evaluate the evolution of soil structure during the process of karst vegetation restoration. The soil structure of sloping fields is the worst Returning farmland to forests is good for soil and water conservation in karst mountainous areas.