Silica, nitrogen and phosphorus dynamics of tallgrass prairie

TitleSilica, nitrogen and phosphorus dynamics of tallgrass prairie
Publication TypeConference Proceedings
Year of Publication1989
AuthorsSeastedt, TR, Ramundo, RA, Hayes, DC
EditorBragg, TB, Stubbendieck, J
Pagination205 -209
PublisherUniversity of Nebraska Press
Conference LocationLincoln, NE
Accession NumberKNZ00252
Keywordstallgrass prairie

Experiments were conducted on big bluestem (Andropogon gerardii Vitman) in the greenhouse and on a tallgrass site on Konza Prairie to evaluate the effects of simulated grazing on the cycling of silica (SiO2), nitrogen, and phosphorus. Concentrations of all elements increased in vegetation that had been clipped or pruned. The absolute amount of nitrogen obtained by plants in the greenhouse experiment was increased by clipping foliage. Phosphorous exhibited only neutral or negative responses, while the absolute amount of silica declined in all but one experiment involving root pruning. In that experiment, the absolute amount of silica in roots was increased by 25% by cutting a portion of the root system. These results suggest that the direct effects of clipping or pruning on the absolute amounts of elements cycled through vegetation are usually neutral or negative. Increased silicification or grazed foliage is suggested to be a consequence of delayed senescence and reduced leaf area. This interpretation provides a proximate reason why silicification is an "inducible defense" against herbivores. Key words: big bluestem, Andropogon gerardii, simulated grazing, nutrients, productivity, roots, Kansas