Comparative performance and restoration potential of two Albizia species planted on mine spoil in a dry tropical region, India

This study focussed on the comparative impact of young high density plantations of two Albizia species (Albizia lebbeck and Albizia procera) on the soil redevelopment process during early phase of mine spoil restoration in a dry tropical environment. Plant-hostile features such as high levels of pyrites, etc. were not present. We compared vegetational (biomass, net primary production (NPP). production efficiency, litter fall and its decomposition rate) and soil characters (soil nutrients, microbial biomass and N-mineralization rate) for these plantations. The A. lebbeck plantation accumulated greater biomass and exhibited higher net primary production than the A. procera plantation. The tree layer NPP of A. lebbeck plantation at 6 years age (25.4 t ha(-1) years') was even higher than that of native dry deciduous forest. The short-lived components (foliage, fine roots) accounted for a greater proportion of ecosystem function (productivity) than the long-lived component (stem). The efficiency of foliage for NIPP was greater in A. lebbeck than in A. procera. Decomposition of leaf litter of A. lebbeck was faster than that of A. procera. Ninety five percent mass loss of leaf litter would require 922 days in A. lebbeck and 1328 days in A. procera. Amounts of N and P deposition through leaf fall and release of these nutrients increased with the age of plantation in both species but were higher for A. lebbeck plantation. There was a significant improvement in soil properties due to plantation of both species, but the organic C and kjeldahl N levels were higher in A. lebbeck plantation as were the N-mineralization rates and soil microbial biomass. The proportional increase in soil biomass was much higher than that in soil organic C. The study indicated that the restoration efficiency of A. lebbeck was greater than that of A. procera. (C) 2004 Elsevier B.V. All rights reserved.