Competition has a greater effect than supplemental nutrients on the growth of <em>Sorghastrum nutans</em> and <em>Bromus kalmii</em>

Abstract

Along with many environmental factors, nutrient availability and competition influence the success of grasses on the prairie (Tilman, 1999.) This study examines the influence of these factors on the growth of two grass species: Sorghastrum nutans and Bromus kalmii. Both species received a supplemental nutrient treatment in both competition and noncompetition scenarios. We predicted that nutrients would increase biomass, growth rate, and height, and that supplemental nutrients would give B. kalmii an advantage over S. nutans when the two species were competing. The addition of nutrients, however, rarely yielded significant results. Instead, interspecific competition had a greater impact on the growth of both species. Similar to other studies (Haugland and Froud-Williams, 1999), the provision of ample nutrients failed to eliminate the effects of competition. Perhaps this is because plants continued to compete at the root hair level for nutrients, space, and moisture.