SGS-LTER Ecosystem Stress Area - Soil Carbon & Nitrogen in shortgrass steppe on the Central Plains Experimental Range in Nunn, Colorado, USA 1991, ARS Study Number 3

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
Digital Collections of Colorado
(http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429). 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. Water, nitrogen, and water-plus-nitrogen at levels beyond the range normally
experience by shortgrass steppe communities were applied from 1971 through 1975, plant
densities were sampled through 1977, and then sampling resumed in 1982, with sampling
frequencies changing from annually to every other year. The initial sampling from 1970 to
1974 showed that the water and water plus nitrogen treatments had the strongest effect on
plant community structure, both treatments increased biomass, and exotic weed species were
noted on the water plus nitrogen treatment. Later sampling from 1982 to 1991 showed a
ten-fold increase in exotic weed species on the water plus nitrogen plots as compared to
the controls (Milchunas and Lauenroth 1995), a community change that has persisted on this
site due to a chronic elevation of soil nitrogen caused by a plant tissue/soil organic
matter feedback mechanism (Vinton and Burke 1995). In 1998, Six new treatments were
superimposed on the historic study site. The six new treatments were: control, sugar,
lignin, sawdust, lignin and sugar, and sawdust and sugar.In 2010, plots will be sampled
every 5 years. Our objective in this study is to examine how plant communities change
through time and explore implications of these changes for monitoring potentially stressed
ecosystems. Additional information and referenced materials can be found:
http://hdl.handle.net/10217/83317.