稀土矿场植被修复及其对土壤种子库的影响

Phytoremediation in mined rare earth land and its effect on seed bank in soil

为了解稀土矿区人工植物修复效果以及其对土壤种子库的影响,选取广东省平远县废弃稀土矿场修复区为试验点,对矿场修复区植被修复过程中的植被物种变化,以及修复区和距离修复区10、20和30 m未修复区(分别记为A、B、C和D区)的土壤种子库进行了调查.结果表明:1在稀土矿场土壤人工植被修复之后,修复区地表植被覆盖增加,但植被的物种数由2013年11月的16种下降至2014年11月的8种,物种类型由本土植物逐渐占居优势;22013年9月修复区的土壤种子密度(A区:26.86/m^2)高于同期未修复开采区3个样地的土壤种子密度(B、C和D区分别为:3.13、1.50和1.25/m^2),且高于2014年9月修复区与开采区土壤种子库的物种数;3非修复区土壤种子库的数量上明显少于修复区,其大部分物种来源于修复区,且相邻区土壤种子库的物种相似度大于非相邻区.由此表明植被修复对稀土矿场物种多样性增加有明显的效果,对矿区修复区及周边环境土壤的种子库有重要的影响.

In order to observe phytoremediation in mined rare earth land and understand the effect of phytoremediation on the seed bank in soil,this study was carried out in the mining rare earth area in Renju town,Pingyuan County,Guangdong Province. The investigations of plant species and seeds bank were conducted in restored and mining area 10,20 and 30 m apart from rare earth land（ marked as A,B,C and D plots,respectively）. The results showed that： 1the vegetation coverage in restored area increased during phytoremediation,but the species of the vegetation decreased to 8 in November 2014 compared with 16 species in November 2013,and the native plants were dominant gradually; 2seed density（ A plot： 26. 86 / m^2） in restored area was higer than those in the mining area（ B plot： 3. 13 /m^2、C plot：1. 50 / m^2、D plot： 1. 25 /m^2） in september 2013,and plant species were higher than that in restored and mining areas in september 2014; 3the seed density of mining area was lower than restored area in both years,and most of the species were spread from restored area. The similarity of seeds bank in the adjacent region was higher than the non-adjacent region. This study revealed that,phytoremediation was obviously effective in species diversity in rare earth area,and had an important affect on seed banks in soils both in the restored increasing plant and adjacent areas.