An examination of the effects of grazing on vegetative and soil parameters in the tallgrass prairie

Abstract

The effects of grazing on vegetative biomass and richness and various soil parameters in the tallgrass prairie were examined at the Tallgrass Prairie National Preserve (TPNP) and the Konza Prairie Biological Station (KPBS). It is hypothesized that grazing will exert significant influence on vegetative biomass and native species richness, and soil depth, moisture content, pH, nutrient levels (total Kjeldahl nitrogen and total phosphorus), and organic matter content. To test this hypothesis, four sets of samples were gathered: 10 from an ungrazed portion of TPNP and 10 from a grazed portion, 10 from an ungrazed area of KPBS and 10 from a grazed area. Results indicate that grazing decreased vegetative biomass density, increased soil nutrient levels, and increased soil organic matter content. Mixed results were found on the effects of grazing on available soil moisture and soil pH. Soil moisture content was significantly higher in the ungrazed area of TPNP, but significantly higher in the grazed area at KPBS. Soil pH was significantly higher in the ungrazed area of TPNP but no significant differences were observed at KPBS. Grazing did not significantly influence soil depth or species richness, though differences in the taxa of species observed were evident as native grass species richness decreased in grazed areas and invasive species richness increased in grazed areas.