The Role of Microorganisms in the Revegetation of Strip Mined Land in the Western United States

Abstract

This paper discusses the role of microorganisms in the reclamation of spent shale wastes in western Colorado and the overburden from lignite strip-mining areas in North Dakota. Adverse conditions for plant growth such as low organic matter content, salinity, fine texture and a lack of nitrogen and phosphorus, and a slow rate of soil formation limit the revegetation of the mining wastes. Microbial processes are responsible for the accretion of soil organic matter, the fixation of nitrogen, and the modification of adverse soil properties with the spoil. Possible strategies to take advantage of microbial activities to encourage plant growth in strip-mined land are discussed. Fertilization, seeding, mulching, the inoculation of the rhizosphere of perennial grasses with free-living heterotrophic nitrogen-fixing bacteria, and the production of sulphuric acid by sulphur-oxidizing bacteria to lower the pH of the spoil are reviewed.