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ABSTRACT <br />A field study was begun in 1980 to evaluate the effects of <br />soil depth and soil and spoil manipulations on seeded range <br />vegetation. The study site was located at a surface coal mine in <br />northwest Colorado at an elevation of 1980 m. The experimental <br />design included four topsoil depths (15, 30, 45 and 60 cm) and five <br />different combinations of ripping, disking, and fertilization with <br />phosphorus. Aboveground production and canopy cover were estimated <br />yearly for the first five years of the study and then ten years <br />after seeding. Aboveground production and canopy cover at the end <br />of the study were no different between the shallowest and deepest <br />topsoil depths. However, deeper topsoil depths supported a plant <br />community that was dominated by grasses while the shallower topsoil <br />depths supported plant communities that were more diverse and had <br />significantly greater forb production and shrub density. It <br />appears after ten growing seasons that a thin layer of topsoil (15 <br />cm) over non-toxic spoil is sufficient for the establishment and <br />continued productivity of rangeland vegetation. <br /> <br />