Restoration of mine spoil in a dry tropical region: a review

Abstract

Surface mining extensively alters the physical, chemical and biological characteristics of the soil, and therefore, the revegetation of mine spoil through natural process takes a very long time and poses a major problem because nutritionally it is a recalcitrant medium for plant growth. We review important studies on the restoration of mine spoils in the tropical dry region of India. Through this communication, we suggest that the microbial biomass of soil is a critical factor in the recovery of mine spoils because it plays a major role in the re-establishment of nutrient cycling. The levels of microbial biomass C, N and P can be treated as functional indexes for soil re-development. Tree plantations have been reported to significantly accelerate the re-development process. Ground seeding of the mine spoils with suitable tree and grass species together with NPK fertilization has been reported to promote growth, and consequently leads to increase in biomass production. Species-specific variations are reported to occur in the response to fertilization. Relatively, greater variation has been reported for non-leguminous, rather than for leguminous species. Furthermore, leguminous species exhibit higher growth rates as compared to non-leguminous species. Our review also suggests that the microsite conditions on the mine spoils exhibit differences and should be given more consideration for accelerating the process of re-vegetation and fulfilling the post-mining land use objectives.