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0� 0� <br /> Thomas A. Colbert Page 3 <br /> Until not many years ago,the kinetics of sulfide oxidation in the environment were <br /> not well understood. It was then discovered that this oxidation reaction does not <br /> occur at a significant rate unless catalyzed by certain species of chemoautotrophic <br /> bacteria(Thiobacillus)which are ubiquitous in most environments. In the absence <br /> of bacteria,pyrite oxidation practically speaking does not occur. It is now known <br /> that four elements are required for acid formation- <br /> 1) sulfide mineral <br /> 2) oxygen <br /> 3) water <br /> 4) oxidizing bacteria <br /> Eliminating any one of these will effectively halt the process of acid formation. <br /> Depending on the setting, the problem of acid formation may be characterized as a <br /> problem of acid mine drainage,mobilization of toxic metals,acid soils,or any <br /> combination of these. Plant species will not tolerate the severe acid conditions <br /> which can result from the oxidation of pyrite. Studies have shown that liming <br /> treatments are not a permanently effective solution to this problem. <br /> Soil Micmmpnisms and Nutter Cycling <br /> In the past few years, a great deal of research has been conducted relating to the <br /> importance of"below ground reclamation",particularly the re-establishment of soil <br /> microbial populations and the nutrient cycles catalyzed by soil microbes. The <br /> importance of this has been especially recognized for cold regimes,where long <br /> winters and short growing seasons limit the rate of organic matter decomposition in <br /> the soil. <br /> Early reclamation efforts under such conditions often made the mistake of utilizing <br /> non-native improved grass varieties and relatively heavy rates of inorganic fertilizer. <br /> As long as maintenance fertilization was kept up,the vegetation persisted. But it <br /> was soon noticed that under such management,that there would be a build-up of <br /> undecomposed plant litter on the soil surface and that as soon as maintenance <br /> fertilization was withdrawn,vegetation stands would be lost. <br /> Ecologists observed that vegetation loss could often be prevented with the use of <br /> live handled topsoil and species—typically natives—which were not dependent on <br />