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101 <br />density values to exhibit any significant effects caused by the different <br />• levels of fertilization. <br />Effect of Fertilization on the Biomass of Grasses, Forbs, and Shrubs <br />The only significant response of the biomass of grasses, forhs, and <br />shrubs to fertilization occurred in the case of forbs in the seed <br />mixtures. Seeded forbs showed a significant interaction between fertili- <br />zation and panel with respect to biomass (Figure 37). On Panel 6 the <br />plots fertilized with 28 kg P/ha had a significantly greater biomass of <br />seeded forhs than those fertilized with 56 kg P/ha. Biomass response of <br />seeded forbs was significantly higher within the nonfertilized treatment <br />than within the highly fertilized treatment on Panel 3. The data sug- <br />gests that higher fertilization levels of phosphorus may have a detri- <br />mental effect on seed forb biomass, especially in the deeper soil-shale <br />• profiles. <br />Effect of Fertilization on the Cover of Grasses, Forbs, and Shrubs <br />The cover of grasses, forbs, and shrubs showed no significant <br />interactions or differences among fertilization treatments. The high <br />amount of variability in cover values on the subplots caused the failure <br />to see any significant cover response from the fertilization treatments. <br />Conclusions <br />1. Paraho retorted shale, without large inputs of resources and <br />management, cannot be directly revegetated within an environ- <br />mentally acceptable time period. <br />2. The data suggests that deeper soil coverings of 61 and 91.5 cm <br /> <br />• may be necessary over retorted share to establish diverse and <br />1 productive ecosystems. <br />