SGS-LTER Long Term Nitrogen Concentration in LTNPP Monitoring on the Central Plains Experimental Range, Nunn, Colorado, USA 1987 - 2011, ARS Study Number 6

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. Additional information and referenced materials can be found:
http://hdl.handle.net/10217/83462. Aboveground plant nitrogen dynamics monitoring
consists of two separate data sets. a) Long-term
peak-crop nitrogen concentrations have been
sampled since 1983 annually from sites sampled for
ANPP estimates across the CPER. Plots are clipped
for ANPP in August each year and include
moderately grazed sites in sections 24 and 25,
ungrazed treatments at ESA and owl creek, coarse
textured soils in owl creek, fine textured soils
in section 25, as well as three catena
topopositions in section 24. These datasets have
been designed for monitoring and so it is advised
to consider calcuating average based at the
transect level. B) Seasonal dynamics of life-form
(dominant grass, forb, shrub species) nitrogen
concentrations were obtained from random grab
samples of aboveground plant tissue are taken
monthly from May-Aug. and in Oct., Dec., Feb., and
April from 1983 – 2007 at sites where ANPP has
been collected since 1983 (ESA, ridge, mid-slope
and swale in section 24). The objectives are to
assess annual/seasonal weather and site
productivity/management with quantity and quality
of forage and/or litter production. Combined,
these two data sets also provide an estimate of
nitrogen yield. These data can be linked with
secondary producer data sets such as annual cattle
weight gains, grasshopper abundance, small mammal
monitoring, etc., to assess how forage/plant
tissue quantity and quality drive population
dynamics.