Abstract: Revegetation can be a suitable option to control pollution in deserted mining sites. A pot experiment and a field experiment using Robinia pseudoacacia were carried out in a deserted zinc smelting site, typical of Hezhang County, Guizhou Province, China to explore effects of various soil amelioration approaches on soil physical-chemical properties, contents of heavy metals, growth of R. pseudoacacia and limiting factors in revegetation. Results show that the limiting factors in revegetation of slag wasteland of slag were mainly salt-alkali stress, low contents of total N, available N and total K, high concentrations of Pb, Zn and Cd and low water retention capacity. Although elevated Pb, Zn and Cd concentrations were present in the slag wasteland, their exchangeable fractions were low. Amendment of the new slag wasteland of new slags with the soil from the site may lower pH and EC, reduce salt-alkali stress and increase water retention capacity of the land, thus significantly improving the survival and growth rate of R. pseudoacacia therein. Therefore, the amendment was an effective method to ameliorate the substrate or the wasteland for revegetation. Years of leaching significantly reduced salt-alkali stress to the trees, and increased available soil water content of the wastelands. Application of hydrogel or soil from the mining site can effectively help the survive and establish of R. pseudoacacia survive and establish in old slag wastelands.

Key words: Hezhang County, wasteland, revegetation, limiting factors, substrate amelioration, Robinia pseudoacacia