闽南山地3种典型植被类型土壤分形与养分特征

目的]探索闽南山地不同植被类型土壤分形特征及其与表层土壤颗粒组成、养分含量的相关关系,为评价闽南山地典型植被类型土壤质量,开展土地利用结构调整、土壤侵蚀防治及生态修复等提供参考。方法]选取土壤颗粒体积分形维数模型对3种典型植被类型林地土壤的分形维数D值进行计算,并与土壤颗粒组成及土壤养分进行相关性分析。结果]土壤颗粒体积分形维数D值从大到小依次为次生林马尾松林柑橘林;分形维数D值与土壤黏粒和粉粒体积百分数存在显著正相关关系,与砂粒体积百分含量呈显著负相关(p0.05);土壤pH值、全氮、全磷、全钾、水解性氮、有效磷、速效钾和有机碳含量从大到小均为:次生林马尾松林柑橘林;土壤容重为柑橘林马尾松林次生林;分形维数D值与柑橘林的土壤水解性氮含量呈显著正相关,与马尾松林的水解性氮含量、土壤全磷、全钾含量呈显著正相关,与次生林的土壤全磷含量、水解性氮含量呈显著正相关,与有机碳含量均呈显著负相关。结论]闽南山地不同植被类型会显著影响表层土壤体积分形维数及养分含量,利用土壤体积分形维数可一定程度上反映不同植被类型的土壤颗粒组成及其养分含量。

Characteristics of Soil Fractal and Nutrient Under Three Typical Vegetation Types in Mountainous Region of Southern Fujian Province

Objective] In order to provide theoretical basis for the evaluation of mountain soil quality under typical vegetation types, land use structure adjustment, soil erosion control and ecological restoration in Southern Fujian Province, we explored the fractal characteristics of soils under different vegetation types in Southern Fujian Province and analyzed the correlations of fractal characteristics with soil particle composition and nutrient content.Methods] The fractal dimension D values of the soil under three typical vegetation forests in a mountainous region of Southern Fujian Province were calculated using the fractal dimension model of soil particle volume, and their correlations with soil particle composition and soil nutrients were analyzed.Results] The fractal dimension D values of the soil particle volume, in descending order, were the secondary forest, the Masson pine forest, and the citrus forest respectively. The fractal dimension D value was significantly and positively correlated with the volume percentage of the soil particles of clay and that of powder, and significantly and negatively correlated with the mass percentage of the sand(p<0.05). With regard to the soil pH value, the contents of total nitrogen, total phosphorus, total potassium, hydrolytic nitrogen, available phosphorus, available potassium and organic carbon, their descending order was secondary forest> Masson pine forest > citrus forest; while for soil bulk density, it had a rank as citrus forest > Masson pine forest > the secondary forest. The correlation analysis showed that the fractal dimension D value was significantly and positively correlated with the content of hydrolytic nitrogen in the soil of citrus forest, while it was significantly and negatively correlated with its organic matter. With respect to the Masson pine forest, it had a significant positive correlation with the contents of total phosphorus and total potassium in the soil, and had an extremely significant and positive correlation with the content of hydrolytic nitrogen. At the same time, it had a significant negative correlation with the content of organic carbon. With respect to the secondary forest, it had an extremely significant positive correlation with the content of total phosphorus in the soil(p<0.01), a significant positive correlation with the content of hydrolytic nitrogen, a significant negative correlation with the content of available potassium and organic carbon.Conclusion] Vegetation types in the southern Fujian mountain area significantly affected the fractal dimension and nutrient contents of the surface soil, and it is possible to use the soil fractal dimension to reflect the soil particle composition and nutrient contents of different vegetation types.