EFFECTS ON SOIL CARBON AND NITROGEN CYCLING ASSOCIATED WITH GRAZING BY DIFFERENT SPECIES IN A KANSAS TALLGRASS PRAIRIE
Social Sciences
NSF Research Experience Undergraduate (REU) Program and ENVS 195
The world’s soils are an enormously important sink of atmospheric CO2, sequestering significantly more carbon. Consequently, alterations to soil carbon cycling can have huge implications concerning climate change. In cases of heavy grazing, intensity- reduction or exclusion has been shown to increase primary productivity and sequester carbon, as opposed to release. However, these studies focus on sheep or cattle-grazed land. It has been almost 30 years since the near-extinction of the Plains bison in Midwest America and their numbers are returning. Aboveground comparisons have been made between cattle and bison- grazed lands, but not much has been researched belowground. This experiment conducted on Konza Prairie Biological Station (KPBS), a tallgrass prairie in Manhattan, Kansas, analyzes root and soil properties, using microbial biomass carbon (MBC), total nitrogen (TN) and total carbon (TC) as proxies for carbon and nitrogen cycling. MBC content was over 60% greater, while TC and TN were 40% and 35% greater respectively in the bison-grazed site compared to cattle- grazed. These differences are quite significant and could have long lasting effects on soil nutrient cycling in middle North America.
