Restoration Effect of Young Plantations on Magnesite Mine Spoil in Northeast China

We compared the effects of young plantations (4 to 5 years old) of two trees (Ulmus pumila and Robinia pseudoacacia (a legume)) and a shrub (Ziziphus jujube var. spinosa) on soil carbon and nutrient concentration, microbial biomass and their accretion during early phase of plantation establishment on mine spoils around a magnesite mine in Northeast China. There was a slight increase in soil total organic C (TOC), total N (TN), and a significant increase in microbial biomass C (MBC) and microbial biomass N (MBN) after restoration of 4 to 5 years for all the three species. Soil TOC, TN, MBC and MBN increased the most in R. pseudoacacia plantation than that in Z. jujube var. spinosa and U. pumila plantation. No significant differences in total P accretions were found among all treatments. These results indicated that soil quality was substantially improved during early phase of plantations establishment for all species. All the three species are promising for ecological restoration of mine spoils around magnesite mine regions, especially R. pseudoacacia has stronger impact on soil improvement.