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58 <br /> <br /> <br /> <br />As noted in previous recommendation sections, the performance of the treatments • <br />in the experimental design must be viewed against the status of the Reference <br />Areas (Figures 10-12) to see if our work can sufficiently restore the land to <br />predisturbance levels of vegetation growth and ecosystem stability. Vege- <br />tatively, given the eight treatments designed and monitored, we do not have <br />the capability to reclaim the land to a compatible level with the adjacent <br />undisturbed areas. Plant response on Treatment 2 yielded 80% of the biomass <br />produced on the reference sites with the other amended spoils displaying a ~ <br />wide range of responses (Figure 10). Cover on Treatment 2, which exhibited <br />the greatest value in the Main Plot, was only one-half of that occurring in <br />the natural ecosystem. Finally, density which is lower by a factor of 70% to <br />80 ;, differs markedly from the Reference Areas too. ~ <br />Since the implementation of this study in 1976 plant biomass and cover <br />values have steadily shown an increase as species have become established, - . <br />with density displaying a moderate decline thorugh time as the plant canopy <br />and root networks closed (past progress reports). Considering the young age <br />of the revegetation plots and the suboptimal seedbed characteristics created <br />by the black carbonaceous spoils, one might anticipate that with time plant <br />productivity and cover will rise as the various life forms modify the. micro- <br />environment more to their suitability. Only density will probably remain far <br />below that found in the Reference Areas for some time due to characteristics <br />of the seeded species themselves. Their keen competition for site occupation <br />and resource exploitation favors vegetative growth at the expense of reproduc- <br />tive organs. Also, most of the seeded species are not as prolific seeders as <br />weedy species like kochia which was found to contribute significantly to the <br />very high density values observed on the undisturbed areas. Given that our <br />treatments exhibit a trend towards increased stand development, coupled with . <br />