ABSTRACT
Several studies focused on the effects of organic mulches on soil biota and soil processes in surface mined areas are reviewed. The effects of overgrazing and subsequent rangeland degradation on soil processes are described. Amending mine spoil materials with recalcitrant mulch materials, bark and wood chips, resulted in increased abundances and diversity of soil microflora and microfauna which resulted in decomposition rates similar to unmined soils. Other organic mulches, straw and sewage sludge, had short term or no effect on biota and decomposition. On surface mined areas reconstructed by contouring with a surface layer of topsoil amended with straw, the soil biota and processes were most similar to unmined soil the first year post restoration and diverged greatly by the fourth year. This restoration procedure failed to maintain a viable soil biota. Addition of organic amendments to intact but degraded rangeland had no long-term effect on soil processes, soil biota or vegetative production. In arid rangelands the shift in vegetation from grassland to shrubland has resulted in lowered nitrogen availability as evidenced by low total soil nitrogen and reduced nitrogen mineralization potential.
