Burke, Ingrid C.2007-01-032007-01-031997-2012http://hdl.handle.net/10217/85547http://dx.doi.org/10.25675/10217/85547Natural Resource Ecology Laboratory (NREL)Shortgrass Steppe-Long Term Ecological Research (SGS-LTER)This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Repository (http://hdl.handle.net/10217/100254). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. In a 10-year study, we assessed the influence of five carbon (C) treatments on the labile C and nitrogen (N) pools of historically N enriched plots on the Shortgrass Steppe Long Term Ecological Research site located in northeastern Colorado. For eight years, we applied sawdust, sugar, industrial lignin, sawdust + sugar, and lignin + sugar to plots that had received N and water additions in the early 1970s. Previous work showed that past water and N additions altered plant species composition and enhanced rates of nutrient cycling; these effects were still apparent 25 years later. We hypothesized that labile C amendments would stimulate microbial activity and suppress rates of N mineralization, whereas complex forms of carbon (sawdust and lignin) could enhance humification and lead to longer-term reductions in N availability. Results indicated that of the five carbon treatments, sugar, sawdust, and sawdust + sugar suppressed N availability, with sawdust + sugar being the most effective treatment to reduce N availability. The year after treatments stopped, N availability remained less in the sawdust + sugar treatment plots than in the high-N control plots. Three years after treatments ended, reductions in N availability were smaller (40-60%). Our results suggest that highly labile forms of carbon generate strong short- term N sinks, but these effects dissipate within one year of application, and that more recalcitrant forms reduce N longer. Sawdust + sugar was the most effective treatment to decrease exotic species canopy cover and increase native species density over the long term. Labile carbon had neither short- nor long-term effects on exotic species. Even though the organic amendments did not contribute to recovery of the dominant native species Bouteloua gracilis, they were effective in increasing another native species, Carex eleocharis. These results indicate that organic amendments may be a useful tool for restoring some native species in the shortgrass steppe.ZIPJPEGPDFTXTXMLengData sets were provided by the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Program, a partnership between Colorado State University, United States Department of Agriculture, Agricultural Research Service, and the U.S. Forest Service Pawnee National Grassland. Significant funding for these data was provided by the National Science Foundation Long Term Ecological Research program (NSF Grant Number DEB-1027319). The SGS-LTER project (1980-2014) was established as one of the first sites in the US LTER Network and has produce a rich legacy of digital materials including reports, proposals, images, and data packages. Data, products and other information produced from the SGS-LTER are curated as a collection within the Repository (http://hdl.handle.net/10217/100254). Materials can be accessed from the Institutional Digital Repository of Colorado State University or upon request by emailing ecodata_nrel@colostate.edu. All data are open for dissemination and re-use for any purpose, but you must attribute credit to the owner and cite use appropriately according to the LTER Data Access Policy (http://www.lternet.edu/policies/data-access).plantscovercarbonpopulationsdisturbanceDataset