SGS-LTER Transect Study - Organic Carbon in Soils across Toposequences on the Central Plains Experimental Range, Nunn, Colorado, USA 1983-1984

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. CPER SOC across Toposequences - Pedons and
their corresponding topography were described
along an 8 km transect oriented normal to the
major drainages of the CPER. A total of 140 pedons
representing 23 toposequences and 7 plains
segments were characterized. Sampling sites were
selected within toposequences according to slope
position (summit, shoulder, backslope, footslope,
toeslope) and within plains segments at
approximate 100 m intervals. Pedons were described
and sampled by genetic horizon according to the
standards of the National Cooperative Soil Survey.
Analyses, conducted at Colorado State University,
included particle size and organic C. Bulk density
was estimated empirically according to: Rawls,
W.J. 1983. Estimating soil bulk density form
particle size analysis and organic matter content.
Soil Sci 135: 123-125. Organic C accumulation was
measured along an 8 km transect at a site in the
semiarid shortgrass steppe of northeastern
Colorado. Specific objectives of the study were to
(I) measure the quantity and distribution of
organic C across toposequences, (ii) test the
hypothesis that a disproportionate amount of soil
organic C resides in the lowlands (as defined
herein), and (iii) assess the role of geomorphic
history as a determinant of contemporary rates of
biogeochemical organic C transformations. Results
of the study showed the surface (A) horizon
organic C concentration did not vary
systematically among slope positions of a given
toposequence. Similarly, the mass of organic C
within the surface meter of soil often did not
increase with decreasing elevation across a
toposequence. Mass of organic C was found to range
from 2.5 kg m^-3 on terrace escarpments to 10.7 kg
m^-3 on sandy uplands. The mass of organic C, as
calculated to the BCk horizon, was highest in the
lowlands. The mass of buried organic C, as
calculated uniformly for a 50 cm thickness of
material, represents 17% of the total organic C
estimate for the site. In spite of buried soils,
lowlands did not contain a disproportionate amount
of total landscape organic C. Additional information and referenced materials can be found: http://hdl.handle.net/10217/85625.