Rosario Karyna, Iverson Sadie L, Henderson David A, Chartrand Shawna, McKeon Casey, Glenn Edward P, Maier Raina M
Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ 85721-0038, USA.
J Environ Qual. 2007 Jul 17;36(5):1249-59. doi: 10.2134/jeq2006.0315. Print 2007 Sep-Oct.
Mine tailings are moderately to severely impacted sites that lack normal plant cover, soil structure and development, and the associated microbial community. In arid and semiarid environments, tailings and their associated contaminants are prone to eolian dispersion and water erosion, thus becoming sources of metal contamination. One approach to minimize or eliminate these processes is to establish a permanent vegetation cover on tailings piles. Here we report a revegetation trial conducted at a moderately impacted mine tailings site in southern Arizona. A salt and drought-tolerant plant, four-wing saltbush [Atriplex canescens (Pursh) Nutt.], was chosen for the trial. A series of 3 by 3 m plots were established in quadruplicate on the test site to evaluate growth of four-wing saltbush transplants alone or with compost addition. Results show that >80% of the transplanted saltbush survived after 1.5 yr in both treatments. Enumeration of heterotrophs and community structure analysis were conducted to monitor bacterial community changes during plant establishment as an indicator of plant and soil health. The bacterial community was evaluated using denaturing gradient gel electrophoresis (DGGE) analysis of 16S rDNA PCR gene products from tailings samples taken beneath transplant canopies. Significant differences in heterotrophic counts and community composition were observed between the two treatments and unplanted controls throughout the trial, but treatment effects were not observed. The results suggest that compost is not necessary for plant establishment at this site and that plants, rather than added compost, is the primary factor enhancing bacterial heterotrophic counts and affecting community composition.
矿尾矿是受到中度至重度影响的场地，缺乏正常的植被覆盖、土壤结构和发育以及相关的微生物群落。在干旱和半干旱环境中，尾矿及其相关污染物容易受到风蚀扩散和水蚀作用，从而成为金属污染的来源。减少或消除这些过程的一种方法是在尾矿堆上建立永久性植被覆盖。在此，我们报告了在亚利桑那州南部一个受到中度影响的矿尾矿场地进行的植被恢复试验。试验选用了一种耐盐耐旱植物——四翅滨藜[Atriplex canescens (Pursh) Nutt.]。在试验场地设置了一系列3×3米的样地，重复四次，以评估单独种植四翅滨藜移植苗或添加堆肥时其生长情况。结果表明，在两种处理方式下，超过80%的移植滨藜在1.5年后存活。进行了异养菌计数和群落结构分析，以监测植物定植过程中细菌群落的变化，作为植物和土壤健康的指标。使用变性梯度凝胶电泳（DGGE）分析从移植苗冠层下方采集的尾矿样品中的16S rDNA PCR基因产物，对细菌群落进行评估。在整个试验过程中，两种处理方式与未种植对照之间在异养菌数量和群落组成上存在显著差异，但未观察到处理效果。结果表明，在此场地植物定植不需要堆肥，植物而非添加的堆肥是提高细菌异养菌数量和影响群落组成的主要因素。
