30年来东南红壤丘陵区土壤侵蚀度时空演变研究——以长汀县为例

Evolution of Soil Erosion Degree in 30 Years in Granite Hills,Southeastern of China——A Case Study of Changting County,Fujian

土壤侵蚀动态监测是侵蚀研究体系中的重要内容,当前国内大部分研究直接引用国外监测模型,不仅在因子选取以及模型通用性上存在不足,而且对区域土壤的潜在性侵蚀危险考虑不够。因此,研究提出土壤侵蚀度的概念,作为区域土壤实际侵蚀强度与潜在侵蚀危险的综合表征,并基于人地关系系统,通过多指标的量化与建模进行土壤侵蚀度测算,从而分析福建省长汀县土壤侵蚀时空演变规律。结果表明,长汀县土壤侵蚀分布存在集中连片的特点,汀中地区的侵蚀度最高,并向周边逐渐衰减。同时,侵蚀度在变化方向上虽然存在不确定性,但总体侵蚀状况近30a来得到了明显的改善,安全区的比重从1975年的3.87%增长至2006年的56.38%,相比而言,极度侵蚀危险区的比重仅从1975年的12.3%,减少至2006年的6.66%,改善幅度较其他等级土壤有所差距,这与区域在立地条件、经济发展水平以及政策导向上的差异密切相关。研究结果说明选取侵蚀影响因子具有一定的适宜性,也证明土壤侵蚀度可以有效表征土壤侵蚀时空演变趋势。

Monitoring the soil erosion dynamically is an important part in soil erosion research. The studies in China always adopt the quantitative model which were developed abroad, so the shortage is existed in factors selection and commonality of the model, and such studies are also considered less in erosion potentiality. As a result, a concept of erosion degree is proposed in the study, which is a consolidated representation of actual erosion intensity and potential erosion risk. Based on human-land relationship system, the erosion degree were calculated by quantification of multi index, and the spatial and temporal soil erosion degree transition tendency in Changting County, Fujian Provience was analyzed. The results show that characteristics of concentration and contiguous are existed in erosion distribution, the highest erosion degree is existed in central of Changting County, and gradually decay to the surrounding area. On the other wise, although the uncertainty is existed in transition of soil erosion degree, the soil erosion had improved in the passed 30 years, the proportion of safe area in 1975 was 3.87%, and it rose quickly to approximately 56.38% in 2006. In contrast, the decrease rate of extremely dangerous area is less than the other areas, the proportion only reduced from 12.3% in 1975 to 6.66% in 2006. The phenomenon is closely related with the region differences in habitats, economic development and policy orientation. In generally, the result not only certify the suitability in the selection of erosion factors, but also indicted that the erosion degree can characterize the transition tendency of soil erosion.