植被恢复对南方红壤侵蚀区稀土迁移及阻控的影响

Effects of Vegetation Restoration on REEs Migration and Control in Red Soil Erosion Area in Southern China

为阐明在南方花岗岩红壤侵蚀区植被恢复对稀土迁移的影响,探讨稀土迁移的植物阻控效应,本研究以空间序列代替时间序列法选取不同治理年限下的典型样地,深入剖析其稀土含量特征,旨在量化评估生态林草措施下不同治理年限内阻控稀土迁移的生态效应。结果表明,水土流失样地随着生态恢复年限的增加,植被覆盖度的提高,植物种类的丰富,水土流失地土壤环境得到了改善,表层稀土流失也呈现出下降的趋势;土壤-芒萁系统中,稀土元素生态富集系数A_(x)呈现出先增加后下降的趋势,说明了土壤中稀土含量的增加短期内促进了稀土元素向芒萁植物叶片的迁移。芒萁植物叶片优先富集土壤中的轻稀土元素,充分体现出超累积植物芒萁一定程度上可阻控稀土元素向下游迁移,有可能达到生物调控环境中稀土污染的目的。研究成果可为拓展南方红壤侵蚀区稀土迁移的生物阻控提供科学依据。

The purpose of this study is to clarify the effect of vegetation restoration on REEs migration in the eroded granite red soil area in southern China,and to explore the plant control effect of controlling REEs migration.Taking typical plots under different treatment years in Changting county of Fujian province as the study cases,the characteristics of REEs content and the ecological effect of controlling REEs migration under ecological forest and grassland measures were analyzed by using spatial series instead of time series method.The results show that with the increasing vegetation coverage and plant species,the condition of soil and water loss has been improved,so as to reduce the surface REEs loss.On the other hand,in the soil-Dicranopteris dichotoma system,the REEs enrichment coefficient A_(x) had the trend of firstly increasing and then decreasing,indicating that the increase of REEs in soil can promote the REEs migrating to the leaves of the Dicranopteris dichotoma in a short time.Moreover,the leaves of the Dicranopteris dichotoma were priority to the enrichment of LREE in the soil,which indicates that Dicranopteris dichotoma can control REEs migration to a certain extent and may prevent REEs pollution by biological measures.In a word,the results can provide a scientific basis for expanding the biological control of REEs migration in the red soil erosion area of southern China.