The severe exploration of ionic rare earth mine has resulted in a large area of mine tailings abandoned in south China. This has also caused serious vegetation loss, water and soil erosion, and land collapse, which pose a potential risk to the local environment and habitants. In general the rare earth mine tailings have poor soil properties with a lack of organic matter and nutrients, markedly limiting the growth of plants and ecological restoration. Therefore, there is a need to improve the soil properties for accelerating the revegetation process through artificial interference such as soil amendments. In this paper, rare earth mine tailings were amended with four organic materials(i.e. rice straw, sawdust, municipal sludge, chicken manure) and biochar derived from kenaf(Hibiscus cannabinus) straw prior to plantation. Two grass species(i.e. Pennisetumamericanum × P. purpur hybrid and H. cannabinus) were grown in the amended tailings to study their effects on soil properties improvement. The results showed that ① single application of four organic amendments significantly increased the biomass of Pennisetumamericanum × P. Purpur, in which chicken manure exhibited the best effect. However, addition of chicken manure resulted in a higher loss(73.8%) of organic matter compared to sawdust(16.0%), suggesting a weaker organic matter holding durability of the former. ② Compared to the single application, a combination of chicken manure with biochar or sawdust significantly enhanced the growth of H. cannabinus, and increased organic matter content and soil water holding capacity as well. Moreover, this combination amendments mitigated the loss of soil nutrients and organic matter(45.4%). Therefore, we suggest that amendments of chicken manure combined with biochar or sawdust could be a useful means, regarding their better organic matter holding durability and low environmental risk, for revegetation of rare earth mine tailings.
Acta Scientiae Circumstantiae
ionic rare earth mine tailings
Pennisetumamericanum × P.purpur hybrid