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i <br />61 <br />• ( Species Evaluation Plot <br />1 The species found to successfully survive in this plot, that are not <br />presently growing in the Main Plot, should be considered in future seeding <br />mixtures. Because of the nature of this plot, the plants are subject only to <br />intraspecific competition for moisture and nutrients; a situation often more <br />severe than interspecific competition because plants of the same species have <br />similar requirements. A complete test of a species' success will require the <br />interspecific competition of growing in a mixture of species. <br />Trends <br />Plant establishment and early growth is favored on those treatments <br />I receiving nitrogen and mulch amendments. Of the four treatment combinations <br />• tested, 66 kg N/ha + excelsior matting proved most effective. Thus if vitro- <br />- gen is applied during reclamation, it appears that the lower level is adequate. <br />Straw mulch was less satisfactory than excelsior far several reasons: first, <br />J the straw contained a high viable count of invading species which introduced <br />a large amount of competition to seeded species during early stages of plant <br />establishment, and second, the plastic netting over the straw inhibited plant <br />growth during the first three years of growth. <br />Invasion by native species from areas surrounding the ttain Plot was very <br />prominant on all nitrogen amended spoils, including mulched and nonmulched, in <br />the early years following seeding. Competition from these species have proved <br />critical as nutrients have become mare limiting and irrigation ~.aater was <br />withheld. <br />In 1980, Treatment 2 (phosphorus and potassium only) emerged as the most <br />• productive treatment. This result was several years in the making. To begin, <br />early applications of nitrogen to certain treatments favored grass growth at <br />