宁德市土壤侵蚀及其垂直格局特征研究

Studies on Soil Erosion and Its Characteristics of Vertical Patterns in Ningde City

基于修正通用土壤流失方程RUSLE,对宁德市土壤侵蚀进行模拟,分析了该地区土壤侵蚀强度及其垂直格局特征。结果表明：宁德市年土壤侵蚀总量为2.82×10^7t,平均侵蚀模数为22.12 t/（hm^2·a）,属于轻度侵蚀。土壤侵蚀空间异质性明显,总体呈西、北部高,东、南部低,中部略高的格局特征。土壤侵蚀格局与高程存在明显相关性,且在垂直梯度上存在一定的差异,表现为：高度与土壤侵蚀程度、景观破碎化程度和景观多样性正相关,与土壤景观形状复杂性和连通性负相关;低、中、高海拔之间土壤侵蚀差异性显著;在较低和较高海拔地区,土壤侵蚀格局变化幅度较大,而在中等海拔地区较为稳定。

Based on the RUSLE model, the soil erosion in Ningde City was simulated, and the intensity of soil erosion and its characteristics of vertical patterns were analysed. The results have shown that the annual soil erosion in Ningde City amounts to approximately 28.2 million tonnes with average erosion modulus of 22.12 t/ha/yr for the entire region being a kind of mild erosion. Spatial heterogeneity of the soil erosion is evident presenting a feature of being higher in the west and north, lower in the east and south whilst slightly higher in the centre. There is obvious correlation between the soil erosion pattern and site elevation, whilst some differences in vertical gradient exist showing that the elevation is positively correlated with the extents of soil erosion and landscape fragmentation as well as with the landscape diversity, and is negatively with the landscape shape complexity and connectivity. The soil erosion occurred at low, medium or high altitude is signifi cantly different. The soil erosion pattern changes greatly in the area of lower or higher altitude, and is relatively stable at medium altitude area.