川中丘陵区不同治理模式对土壤微团聚体分形特征的影响

探讨川中丘陵区不同小流域治理模式对土壤微团聚体分形特征的影响,可为该区植被恢复与水土流失治理模式提供科学依据。本文通过室内分析,研究了5种不同小流域治理模式下的土壤微团聚体粒径组成、分形维数特征及其与土壤理化性质的关系。1该区土壤微团聚体组成以0.01~0.05 mm粒径为优势粒径,含量在0~10 cm和10~20 cm土层分别达28.63%和28.04%;0.001~0.005 mm粒径为次优势粒径,在0~10 cm和10~20 cm土层含量分别达25.90%和26.33%;各土层不同治理模式下各粒径微团聚体含量差异显著。2该区土壤微团聚体分形维数变化范围为2.643~2.717,不同治理模式土壤微团聚体分形维数呈现水保林甜橙林核桃林裸地坡改梯坡减缓的规律,分形维数与各粒径微团聚体含量呈线性关系。3相关性分析表明,土壤微团聚体分形维数与速效钾、全钾呈正相关,与土壤总孔隙、碱解氮、全氮、有机质呈负相关关系。土壤微团聚体分形维数能较好地反映川中丘陵区土壤的理化结构,是表征该区土壤理化性质的重要指标,林地是该区植被恢复与水土流失治理选择的最优模式。

Effects of different governance patterns of small watershed on fractal features of soil micro-aggregates in the hilly areas of central Sichuan Basin

The exploration of the fractal features of soil micro-aggregates under different governance patterns of small watershed can provide scientific basis for vegetation restoration and for soil and water loss control in the hilly areas of Sichuan Hilly Basin. Thus this paper analyzed the composition and fractal features of soil micro-aggregates and its relationship with soil physicochemical properties. The results showed that soil micro-aggregates of 0.01-0.05 mm size were dominant aggregates in 0-10 cm soil layer (28.63%) and 10-20 cm soil layer (28.04%). This was followed by soil micro-aggregates of 0.001-0.005 mm size for 0-10 cm soil layer (25.90%) and 10?20 cm soil layer (26.33%). Significant differences were observed among different patterns of governance. The range of fractal features of soil micro-aggregates was 2.643-2.717. The sequence of fractal features of soil micro-aggregates for different governance patterns was conservation forest < orange forest < walnut forest < bare-land < slope-terrace < grading of slope land. Linear relation between fractal features and composition of soil micro-aggregates was observed. Fractal features of soil micro-aggregates showed significant positive correlations with available K and total K. However, negative correlations were noted between fractal features of soil micro-aggregates and total soil porosity, alkali-hydrolyzable N, total N and organic matter. The fractal features of soil micro-aggregates better reflected the physicochemical properties of soils in the hilly areas of central Sichuan Basin. Woodland was the best mode for vegetation restoration and controlling soil and water loss in the basin.