Do soil nutrients mediate competition between grasses and Acacia saplings

摘要: The structure and composition of savanna vegetation is influenced by resource availability disturbance. Grasses, a major component systems, influence the tree-grass balance competing with trees for light, water soil nutrients as well providing fuel fires. Overgrazing, ensuing decreased grass competition fire effects resulting from diminished vigor cover, are thought to be drivers bush encroachment. To investigate impacts on saplings Acacia karroo Hayne. nilotica (L.). Willd. ex. Del. under high low fertility, six species, Aristida junciformis (Trin & Rupr.), Eragrostis capensis (Thunb.) Trin., Hyparrhenia hirta Stapf., Panicum maximum Jacq., Sporobolus africanus (Poir.) Robyns Tournay Themeda triandra Forssk., were planted in pots tree sapling central test species. competitive experienced dependent nutrient level identity species (P < 0.001). Aboveground A. was more strongly affected conditions, whereas an increase had little effect between grasses also belowground; however, opposite trend observed one most reducing aboveground biomass 85% 65% respectively, belowground 71% average. Increasing resulted exerted all but no change nilotica. Changes thus likely status.