Acid Mine Wasteland Reclamation by Juncus ochraceus Buchen as a Potential Pioneer Plant

Abstract

Ecological reclamation is the major method for the revegetation of acid mine wasteland worldwide. In this study the pH, fertility characteristics, and heavy metal content of soils from Laili Mountain mine wasteland were analyzed. The research also studied the morphological characteristics and the heavy metal in Juncus ochraceus Buchen as well as its resistance to acid, adaptability to soil fertility in abandoned land, and tolerance to heavy metal pollution (e.g., Zn and Cu) to determine its remediation potential as a pioneer plant for acid mine wasteland. Results showed that the pH of soils in the study area were acidic, ranging from 3.46 to 4.01.The contents of organic matter, total potassium, total phosphorus, and available phosphorus was poor, being 10.28-25.75 g·kg-1, 8.84-9.32 g·kg-1, 0.56-0.63 g·kg-1, and 1.82-5.72 mg·kg-1 respectively.The contents of Zn, Cu, and Fe in the soil ranged between 54.93 and 114.49 mg·kg-1, 92.53 and 127.59 mg·kg-1, and 47133.60 and 112259.63 mg·kg-1, whereby the Cu content was 1.85-2.55 times higher than the risk screening value. The height of Juncus ochraceus Buchen in the study area ranged from 43.77 cm to 55.42 cm, which was shorter than the average plant height of the control group (51.38-57.66 cm); however, this was not a significant difference, thus indicating that this plant was resistant to acidic soil and heavy metal pollution.Further analysis showed that Juncus ochraceus Buchen had accumulating capacity for both Cu and Zn, and transferring capacity for Zn as well. Thus, it had potential in heavy metal accumulation and absorption.Plant height was significantly related to the available phosphorus content in the rhizosphere soil. In the future, soil fertility could be improved by supplementing fertilizers containing available phosphorus when Juncus ochraceus Buchen is planted on the land of abandoned mines as a pioneer plant. Comprehensive analysis revealed that Juncus ochraceus Buchen had great potential as a pioneer plant to remediate acid mine wasteland.