College of Forestry & Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907-2061, USA.
Chemosphere. 2019 Jan;214:47-54. doi: 10.1016/j.chemosphere.2018.09.087. Epub 2018 Sep 18.
Improving soil fertility is a critical component of abandoned rare-earth mine land (ARL) revegetation. To study the effects of sewage sludge (SS), earthworms, and Jatropha curcas in ARL revegetation, SS (40% in mass ratio) and earthworms (0, 40, 60, and 80 individual adult Eisenia fetida kg) were applied to abandoned rare-earth mine land soil (ARLS) and then J. curcas was grown in a potting experiment. The organic carbon, nutrients (N, P, K) and heavy metals (HMs; Cd, Cu, Zn) contents in ARLS and the biomass and nutrients uptake in J. curcas were significantly increased by SS amendment. Application of 80 individual E. fetida kg significantly increased availability of P and K in SS-amended ARLS relative to other treatments. Earthworms increased the height, ground diameter and biomass of J. curcas, but the promotion of biomass became weaker as earthworm density increased. After J. curcas harvest, the contents of Cd, Cu and Zn in SS-amended ARLS were reduced by 15%, 23%, and 19%, respectively. With the joint application of J. curcas and earthworms, a much larger decrease in contents of Cd (34-40%), Cu (31-44%) and Zn (24-29%) in SS-amended ARLS were observed, and the HMs ecological risks were reduced from "moderate potential" to "low potential". Moreover, J. curcas and earthworms together exerted more reduction in the exchangeable fraction HMs in SS-amended ARLS than J. curcas alone. Our results suggest that the integrated application of SS, earthworms and J. curcas is an effective approach for ARL revegetation.
提高土壤肥力是废弃稀土矿区（ARL）植被恢复的关键组成部分。为了研究污水污泥（SS）、蚯蚓和麻疯树在 ARL 植被恢复中的作用，将 SS（质量比的 40%）和蚯蚓（0、40、60 和 80 条成年赤子爱胜蚓 kg）施用于废弃稀土矿区土壤（ARLS），然后在盆栽实验中种植麻疯树。SS 改良剂显著增加了 ARLS 中的有机碳、养分（N、P、K）和重金属（HM；Cd、Cu、Zn）含量，以及麻疯树的生物量和养分吸收。与其他处理相比，应用 80 条赤子爱胜蚓 kg 显著增加了 SS 改良 ARLS 中 P 和 K 的有效性。蚯蚓增加了麻疯树的高度、地径和生物量，但随着蚯蚓密度的增加，对生物量的促进作用变弱。麻疯树收获后，SS 改良 ARLS 中 Cd、Cu 和 Zn 的含量分别减少了 15%、23%和 19%。随着麻疯树和蚯蚓的联合应用，SS 改良 ARLS 中 Cd（34-40%）、Cu（31-44%）和 Zn（24-29%）的含量有更大幅度的降低，并且 HMs 的生态风险从“中等潜在”降低到“低潜在”。此外，与单独种植麻疯树相比，麻疯树和蚯蚓联合应用在 SS 改良 ARLS 中对可交换态 HMs 的去除效果更好。研究结果表明，SS、蚯蚓和麻疯树的综合应用是一种有效的 ARL 植被恢复方法。
