| Summary: | Two field experiments were established to determine the existence, form, and consistency of competitive hierarchies amongst 12 native prairie grass species: one at Carman, Manitoba in 1995; the other in Winnipeg, Manitoba in 1996. The 12 species were grown in a diallel replacement series experiment with 3 replicates in a randomized block design. In each 3.5 m $\times$ 1.25 m plot, above-ground biomass was harvested, dried, and massed after the first and second growing seasons. Competitive hierarchies were examined using relative yields, aggressivity indices, transitivity analysis, and ordination methods. At both sites, the strongest competitors were all highly productive C$\sb3$ species. In 1996, a separate field experiment was sown in Carman, involving 8 native grass mixture sets, each consisting of a 'control' (i.e. non-adjusted) and 'adjusted' mixture, replicated 3 times using 1.25 m $\times$ 10 m plots. Mixtures were adjusted for differences in species establishment rates and competitive abilities basedon the competitive hierarchies determined from Carman in 1995. (Abstract shortened by UMI.)
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