The S3C database is a pedon-based, site-specific, soil-organic-carbon (SOC) database for mineral soils of the Mississippi River basin. The included soil-carbon and related ancillary data are for 9,215 pedons that were described and sampled by various agencies between 1928 and 1995 and represent 2,719 of the 22,517 officially described soil series catalogued by the U.S. Department of ... Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE (Soil Survey Staff, 2003). The S3C database was originally developed for use in USGS terrestrial-carbon cycling studies in the Mississippi River basin (Sundquist and others, 1998) as part of the U.S. Global Change Research Program, Global Carbon Cycle Program Element (http://www.usgcrp.gov/usgcrp/ProgramElements/carbon.htm). The USGS studies were designed to characterize systems across spatial scales ranging from hillslopes to small watersheds to the large-river systems that comprise the Mississippi River basin. These studies included (1) measurement of SOC erosion, deposition, and transformation at the field scale, (2) measurement and modelling of SOC and sediment transport at the small-watershed scale, and (3) measurement, modelling, and statistical analysis of environmental controls on the geographic distribution of SOC at the large-basin scale.
The S3C database includes both pedon-level and horizon-level data with values for organic carbon, carbonate, bulk density, particle size (total sand, silt, and clay), texture class, pH, water content, and soil volume (particles <2 mm diameter). SOC mass storage (kg m-2) was calculated for each soil horizon and, at the pedon level, for the following standard depth intervals?0 to10, 0 to 20, 0 to 50, 0 to 100, 10 to 20, 20 to 50, and 50 to 100 centimeters. Mass-weighted mean values for carbonate, bulk density, particle size and texture class, pH, water content, and soil volume were also calculated for the standard intervals.
The horizon-level data are provided for those interested in the study of site-specific carbon-cycling processes. The pedon-level data are provided for those interested in regional analysis and modelling.
The S3C database was compiled from the following sources:
1. U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Characterization Database (U.S. Department of Agriculture, 2001?7,821 pedons, 1938 to 1995, geographic coverage?basinwide);
2. two surveys of high-elevation soils in the Southern Blue Ridge (Fenneman, 1938) physiographic province (Daniels and others, 1987a, b?8 pedons, Graham County, North Carolina; Feldman, 1989, 2000, Feldman and others, 1991a, b?37 pedons, Swain and Yancey Counties, North Carolina, Sevier County, Tennessee, Grayson and Smyth Counties, Virginia);
3. University of Arkansas, Soil Characterization Database (University of Arkansas, 2000?495 pedons, 1955 to 1992, Arkansas statewide);
4. University of Illinois, Soil Characterization Database (University of Illinois, 2001?778 pedons, 1928 to 1990, Illinois statewide); and
5. a survey of flood-plain and delta soils in the Mississippi Alluvial Plain (Fenneman, 1938) physiographic province (Schumacher and others, 1988?76 pedons, Louisiana statewide).
The data sources, methods, and formulas used to estimate SOC storage and inventory for these soils are discussed in Buell and Markewich (in press). The S3C database will be updated as significant ?blocks? of new data are received, checked for accuracy, standardized, and merged. The database is downloadable through the links on this page. Three data files (pedon01, horiz01, and taxon01) are provided in Microsoft Access 2000 and tab-delimited ASCII formats (compressed in ZIP or TGZ volumes below). The database dictionaries are provided in Microsoft Excel 2000 (pedvar.xls, hznvar.xls, and taxvar.xls) and HTML (pedvar.htm, hznvar.htm, and taxvar.htm) formats. The database dictionaries are also included in the field definition column of each Access data table (pedon01, horiz01, and taxon01). The footnote references for the field definitions are included in the Access version of the database as separate tables (pedon01-footnotes, horiz01-footnotes, and taxon01-footnotes).
The pedon file (pedon01) contains site-level data such as soil series name and geographic location as well as SOC storage and related ancillary data for standard depth intervals; the horizon file (horiz01) contains the physical and chemical characterization data for individual soil horizons; and the soil-taxonomy file (taxon01) contains the descriptive data for all of the soil series presently described by the U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, Nebraska. The entire soil-series database was included in the taxonomy file to facilitate updates to the pedon and horizon files. As the pedon and horizon files are updated, data for previously unrepresented soil series will likely be added. It is the authors? intent that these data will be helpful to those involved in ecological studies, environmental assessments, and landuse planning efforts that require the use of SOC data.
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Buell, G.R. and Markewich, H.W., in press, Data compilation, synthesis, and calculations used for organic-carbon storage and inventory estimates for mineral soils of the Mississippi River basin, chap. A of Markewich, H.M., ed., Soil-carbon storage and inventory for the continental United States: U.S. Geological Survey Professional Paper 1686.
Daniels, W.L., Everett, C.J., and Zelazny, L.W., 1987a, Virgin hardwood forest soils of the southern Appalachian Mountains: I. Soil morphology and geomorphology: Soil Science Society of America Journal, v. 51, p. 722-729.
Daniels, W.L., Everett, C.J., and Zelazny, L.W., 1987b, Virgin hardwood forest soils of the southern Appalachian Mountains: II. Weathering, mineralogy, and chemical properties: Soil Science Society of America Journal, v. 51, p. 730-738.
Feldman, S.B. 1989, Taxonomy, genesis, and parent material distribution of high elevation forest soils in the southern Appalachians: unpublished M.S. thesis, Virginia Polytechnic Institute and State University, Blacksburg, VA, Appendix B
Feldman, S.B., 2000, unpublished data, provided to USGS in 2000.
Feldman, S.B., Zelazny, L.W., and Baker, J.C., 1991a, High-elevation forest soils of the southern Appalachians: I. Distribution of parent materials and soil-landscape relationships: Soil Science Society of America Journal, v. 55, p. 1629-1637.
Feldman, S.B., Zelazny, L.W., and Baker, J.C., 1991b, High-elevation forest soils of the southern Appalachians: II. Geomorphology, pedogenesis, and clay mineralogy: Soil Science Society of America Journal, v. 55, p. 1782-1791.
Fenneman, 1938, Physiography of eastern United States: New York and London, McGraw-Hill Book Company, 714 p.
Schumacher, B.A., Day, W.J., Amacher, M.C., and Miller, B.J., 1988, Soils of the Mississippi River alluvial plain in Louisiana: Louisiana Agricultural Experiment Station Bulletin No. 796, Louisiana State University Agricultural Center, 275 p.
Soil Survey Staff, 1999, Soil taxonomy, a basic system of soil classification for making and interpreting soil surveys, 2nd ed.: U.S. Department of Agriculture, Natural Resources Conservation Service, Agriculture Handbook Number 436, 870 p.