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SGS-LTER impact of labile and recalcitrant carbon treatments on plant communities in a semiarid ecosystem on the Central Plains Experimental Range, Nunn, Colorado, USA 1997-2012, ARS study number 3

Abstract

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.

Description

Natural Resource Ecology Laboratory (NREL)
Shortgrass Steppe-Long Term Ecological Research (SGS-LTER)

Rights Access

Subject

plants
cover
carbon
populations
disturbance

Citation

Associated Publications

Burke, I. C., E. E. Bontti, J. E. Barrett, P. N. Lowe, W. K. Lauenroth, and R. Riggle, Impact of Labile and Recalcitrant Carbon Treatments on Available Nitrogen and Plant Communities in a Semiarid Ecosystem. Ecological Applications 23, no. 3 (April 2013):537–545. http://hdl.handle.net/10217/85551
Lowe, Petra N., Nitrogen Availability Effects On Exotic, Invasive Plant Species. (Unpublished master's thesis). Colorado State University, 2000. http://hdl.handle.net/10217/82138
Bontti, Eliana E. Microbial Responses to Plant Functional Types and Historical Resources Additions in the Shortgrass Steppe. (Unpublished dissertation). Colorado State University, 2009. http://hdl.handle.net/10217/86389