Restoration of Mine Spoil in a Dry Tropical Region: A Review
Surface mining drastically alters the physical, chemical and biological properties of soil, and therefore, the natural recovery is frequently a slow process. Revegetating coal mine spoil is 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. This report suggests that the soil microbial biomass is a critical factor in recovery of mine spoils as it aids in the re-establishment of nutrient cycling. The levels of microbial biomass C, N and P can be taken as functional indexes of soil redevelopment. Plantation of trees significantly accelerates the soil redevelopment process. NPK fertilization of mine spoils with seeded ground cover promotes growth, and consequently leads to increased biomass production. The response to fertilization varies among species and has been observed greater in non-leguminous than in leguminous species. Furthermore, leguminous species exhibit higher growth rates compared to non-leguminous species. This study suggests that the microsite conditions on the mine spoils should be taken into consideration to accelerate the natural revegetation process according to the post-mining land use objectives.