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33 <br />Discussion <br /> <br />Fertilizer and mulch applications were responsible for the more vigorous <br />plant growth on Treatments 2-7 as compared to the Control. The summary of the <br />soil test data in Table 8 supports this finding. Treatment 1 is deficient in <br />phosphorus, and its overall lower nutrient content suggests the low plant <br />growth. Soils data also show deficiency signs of nitrogen and potassium on <br />Treatment 1. All other treatments likewise indicate these two essential plant <br />nutrients to be limiting, but their low levels of nitrogen and potassium can <br />probably be explained by the more vigorous plant community thriving ort <br />Treatments 2-7 tying up most of the limited available nutrients found •in the <br />soil surface. Also, leaching from the top 10 cm of the spoils has occurred <br />due to a few high intensity storms and heavy rates of irrigation in 1977. <br />Treatment 1 has few nutrients tied up in biomass or in tire soil as reserve. <br />Therefore, if one seeks a floral community with strong vigor and diversity, <br />fertilizer applications seem necessary for initial establishment and later <br />growth of many species on the dolomite wastes. <br />Treatment 6 supported the best plant growth, but it did not ~~~•oduce <br />significantly more biomass, cover, or density than other fertilized treatments. <br />Treatment 2, second only to Treatment 6 in the production of plant biomass, <br />implies that phosphorus may be the key limiting nutrient on this site. The <br />soils data, by showing Treatment 2 to have very similar properties to those of <br />Treatments 3-6, reinforced this conclusion. Finally, amending the spoils with <br />nitrogen and mulch did not significantly (p~.10) increase plant vigor over any <br />treatment except the Control. <br />While community growth showed no response to nitrogen and excelsior, <br />r certain life forms, and thus overall diversity, are influenced by various <br /> <br />