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7 <br />All data were analyzed using analysis of variance procedures. <br />Significant treatment differences were identified with 95$ <br />confidence by the Tukey test (Snedecor and Cochran 1967). <br />RESULTS AND DISCUSSION <br />Plant Community Response Ten Years After Seeding <br />Aboveground Biomass <br />The response to topsoil depth at the end of a ten year period <br />was surprising. Aboveground biomass was significantly greater on <br />60 cm of topsoil than on 45 and 30 cm of topsoil but there was no <br />difference between the 60 and 15 cm treatments (Figure 1). In <br />addition, there were no differences in total aboveground biomass <br />among the 15, 30 and 45 cm depths. Grasses were the dominant life <br />form on all treatments and forbs were a subdominant. Although <br />shrubs were seeded, their contribution to plant community structure <br />was minimal. There was no difference in grass biomass among any of <br />the treatments but forb biomass was greatest on the shallowest <br />topsoil depth (15 cm) and least on the 60 cm treatment (Figure 1). <br />Many scientists working in the field of reclamation have <br />accepted the hypothesis that within certain limits, the greater the <br />topsoil depth the more favorable the plant growth environment and <br />the more productive the plant community (Redente and Hargis 1985, <br />Barth 1984, Hargis and Redente 1984, Redente et al. 1981, McGinnies <br />and Nicholas 1980, Power et al. 1981, Schuman and Power 1981, and <br />Power et al. 1979). Results from this study support this <br />hypothesis but also provide information that indicates that shallow <br />• topsoil depths can also support productive plant communities. we <br />