Soil diagnosis and land suitability assessment for vegetation restoration on coal waste piles in Liupanshui,Guizhou, China

This study analyses physicochemical properties of soils from coal waste piles at the Naluozhai Coal Mine that were dumped 5, 15, 25 and 35 years ago, respectively. The soil at a 20-year old coal waste site where Vetiveria Zizanioides was cultivated was taken as a control. Principal components were analysed to determine their weights, and the weighted summation method was used to calculate soil quality integrated index (SQI). Eight indices were considered to assess land suitability for vegetation restoration, namely pH value, soil layer depth, field moisture capacity, stable infiltration, volume weight, total porosity, organic matter content and vegetation coverage. The results showed that vegetative restoration depends primarily on the organic matter content of the coal waste pile; the control pile recorded the highest SQI and it was satisfactory for vegetation restoration; the 35-year old pile was encouraging for vegetation restoration, second only to the control pile.