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

posted on 2023-11-30, 10:21 authored by Eugene Kelly

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 ( 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:

Resources in this dataset:


Agricultural Research Service

National Science Foundation, DEB 1027319


Data contact name

Kelly, Eugene

Data contact email


Colorado State University

Intended use

Measure the quantity and distribution of organic C across top sequences, estimate the proportion of total soil organic C buried in paleosols.

Use limitations

URL for Access Policies Data Access Policy Data 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 Digital Collections of Colorado ( Materials can be accessed from the Institutional Digital Repository of Colorado State University or upon request by emailing 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.

Temporal Extent Start Date


Temporal Extent End Date



  • Not specified

Geographic Coverage


Geographic location - description

The Short Grass Steppe Site Encompasses A Large Portion Of The Colorado Piedmont Section Of The Western Great Plains. The Extent Is Defined As The Boundaries Of The Central Plains Experimental Range (cper). The Cper Has A Single Ownership And Landuse (livestock Grazing). The Png Is Characterized By A Mosaic Of Ownership And Land Use. Ownership Includes Federal, State Or Private And Land Use Consists Of Livestock Grazing Or Row-crops. There Are Ngo Conservation Groups That Exert Influence Over The Area, Particularly On Federal Lands.

ISO Topic Category

  • environment
  • climatologyMeteorologyAtmosphere
  • biota
  • farming
  • geoscientificInformation

Ag Data Commons Group

  • Central Plains Experimental Range
  • Long-Term Agroecosystem Research

National Agricultural Library Thesaurus terms

agroecosystems; rangelands; sustainable agricultural intensification

OMB Bureau Code

  • 005:18 - Agricultural Research Service

OMB Program Code

  • 005:040 - National Research

ARS National Program Number

  • 215

Pending citation

  • No

Public Access Level

  • Public

Preferred dataset citation

Kelly, Eugene (2013). SGS-LTER Transect Study - Organic Carbon in Soils across Toposequences on the Central Plains Experimental Range, Nunn, Colorado, USA 1983-1984. Colorado State University.