Impact of native tree plantations on mine spoil in a dry tropical environment

This study describes the impact of young high-density plantations of two native leguminous (Albizia procera and A. lebbeck) and one non-leguminous timber tree (Tectona grandis) species on the soil redevelopment process during the early phase of mine restoration in a dry tropical environment. There was a general improvement in soil properties due to establishment of plantations. Highest soil organic C values were found in A. lebbeck plantations and lowest in T. grandis plantations. Both A. lebbeck and A. procera substantially increased levels of nitrogen in soil. However, A. procera, with slow decomposing litter, was not as effective in raising N levels in the soil as A. lebbeck, indicating that all N fixers may not be equally efficient in raising soil N levels. Soil microbial biomass and N mineralization rates were always higher in plantations of N-fixer species. A continued increase with age in microbial C:total C ratio indicates these plantations have yet to reach steady state.