Data dictionary for file 'pedon01', S3C Database, Version 20040427
[USGS, United States Geological Survey; USDA, United States Department of Agriculture; NRCS, Natural Resources Conservation Service; STATSGO, State Soil Geographic; SSURGO, Soil Survey Geographic; VARIABLE FORMAT--Dw.d, where D=data type (C, character; F, floating point; I, integer), w=field width, d=precision; FIPS, Federal Information Processing Standard; NAD, North American Datum; DMS, degrees, minutes, seconds; DD, decimal degrees; %, weight percent; cm, centimeter; mm, millimeter; g cm-3, grams per cubic centimeter; kg m-2, kilograms per square meter; SU, standard pH unit; kPa, kilopascal.  Where variable names have the italicized suffix hh, there is a separate variable in the database for each of the following depth intervals:  0-10 cm (hh = 01), 0-20 cm (hh = 02), 0-50 cm (hh = 05), 0-100 cm (hh = 10), 10-20 cm (hh = 12), 20-50 cm (hh = 25), 50-100 cm (hh = 51).  The methodology for computing standard-interval values is presented in Buell and Markewich (2004, footnote 8).]
VARIABLE NAME	VARIABLE FORMAT (Dw.d)	DEFINITION	UNITS
pedkey	C16	Combination of 'source' and 'idped'.  Primary key ('pedon01' table) linking pedon and horizon ('horiz01' table) records.
source	C4	Origin of source dataset (danl, feld, lasu, nssc, uark, uiuc)1.
idfips	C5	Concatenation of two-letter state abbreviation and county FIPS code.
idped	I9	4-digit calendar year the pedon was sampled * 100000 + a unique pedon identifier.
series	C32	Soil series to which the pedon was classified, either by NRCS or by USGS using NRCS soil series data and USDA-NRCS STATSGO6/SSURGO7 digital soil maps or published USDA-NRCS county soil surveys.  For details on soil-series name assignments, see Buell and Markewich (2003, footnote 8).  Taxonomic link to 'taxon01' table.
year	I4	Year the pedon samples were collected.
county	C32	County in which the pedon samples were collected.
lat	C7	Latitude of pedon location.  Datum NAD27.	DMS
long	C8	Longitude of pedon location.  Datum NAD27.	DMS
dlat	F12.6	Decimal latitude of pedon location.  Datum NAD27.	DD
dlong	F12.6	Decimal longitude of pedon location.  Datum NAD27.	DD
numlayer	I10	Number of mineral horizons in the pedon.
sand_hh	F10.1	Mass-weighted8 mean weight percent (2 mm base, air-dried sample) of particles >0.05 mm and <2.0 mm diameter in the hh cm depth interval measuring downward from the mineral surface (USDA system for classification of soils and sample particle-size data)2,3.	%
silt_hh	F10.1	Mass-weighted8 mean weight percent (2 mm base, air-dried sample) of particles >0.002 mm and <0.05 mm diameter in the hh cm depth interval measuring downward from the mineral surface (USDA system for classification of soils and sample particle-size data)2,3.	%
clay_hh	F10.1	Mass-weighted8 mean weight percent (2 mm base, air-dried sample) of particles <0.002 mm diameter in the hh cm depth interval measuring downward from the mineral surface (USDA system for classification of soils and sample particle-size data)2,3.	%
txclpshh	C8	Texture class of soil based on the mass-weighted8 mean particle size data (total sand+silt+clay) in the hh cm depth interval measuring downward from the mineral surface (USDA system for classification of soils and sample particle-size data)2,3.
bd3_hh	F10.2	Mass-weighted8 mean bulk density (2 mm base) of natural clods (desorbed to 1/3 bar [33 kPa] tension water content2,3) in the hh cm depth interval measuring downward from the mineral surface.	g cm-3
bdod_hh	F10.2	Mass-weighted8 mean bulk density (2 mm base) of natural clods (oven-dried at 105oC2,3) in the hh cm depth interval measuring downward from the mineral surface.	g cm-3
caco3_hh	F10.2	Mass-weighted8 mean weight percent carbonate expressed as equivalent CaCO3 (2 mm base, air-dried sample) in the hh cm depth interval measuring downward from the mineral surface.  Carbonate calculated from manometric measurements of  CO2 evolved from HCl-treated samples2,3.	%
phh2o_hh	F10.1	Mass-weighted8 mean pH equivalent (2 mm base, air-dried sample; pH based on mean hydrogen-ion activity) in the hh cm depth interval measuring downward from the mineral surface. pH is measured in a 1:1 mixture of soil and distilled water2,3.	SU
w15ad_hh	F10.2	Mass-weighted8 mean weight percent gravimetric water content (2 mm base, air-dried sample equilibrated at 15 bar [1500 kPa] tension) in the hh cm depth interval measuring downward from the mineral surface2,3.	%
oc_hh	F10.2	Mass-weighted8 mean weight percent organic carbon (2 mm base, air-dried sample) in the hh cm depth interval measuring downward from the mineral surface. Generally, pre-1995 organic-carbon measurements were done by the Walkley-Black method2,3,4; since 1995 most organic-carbon measurements have been made by dry-combustion to CO2 with quantitation by infrared absorption2,3.	%
ocmc_hhc	F10.2	Mass of organic carbon (2 mm base, 1/3-bar bulk density) in the hh cm depth interval measuring downward from the mineral surface8.	kg m-2
smc_hhc	F10.2	Mass of soil (2 mm base, 1/3-bar bulk density) in the hh cm depth interval measuring downward from the mineral surface8.	kg m-2
svsg_hh	I10	Soil volume (whole-soil base) in the hh cm depth interval in a unit volume of one square meter one centimeter thick (10000 cm3).  This volume is calculated from the coarse-fragment data for each soil series in the USDA-NRCS STATSGO6/SSURGO7 databases.  When multiple records exist for a series, median values are used8.  The calculated soil volume is used to adjust mass storage for the rock volume in the soil profile.	cm3
stempcl	C16	Soil temperature class--soil category based on mean annual or seasonal soil temperatures as defined by the USDA NRCS5.
smregime	C16	Soil moisture regime as defined by the USDA NRCS5.
calrecl	C12	Calcareous reaction class--soil category based on the presence or absence of carbonate, soil reaction, and aluminum concentration as defined by the USDA NRCS5.
mincl	C16	Mineral class--soil category based on the mineralogy of one or more of particle-size components of a soil as defined by the USDA NRCS5.
soilfam	C132	Soil family--the fifth highest level of soil taxonomic classification (subdivision of soil subgroup) as defined by the USDA NRCS5.
1/ danl, 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, or 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.
feld, 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, or 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, or 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, or Feldman, S.B., unpublished data, provided to USGS in 2000.
lasu, Schumacher, B.A., Day, W.J., Amacher, M.C., and Miller, B.J., 1988, Soils of the Mississippi River alluvial plain in Louisiana: Louisiana State University Agricultural Center, Baton Rouge, LA, Louisiana Agricultural Experiment Station Bulletin No. 796, 275 p.
nssc, U.S. Department of Agriculture, Natural Resources Conservation Service, 2001, National Soil Characterization Database, accessed September 1, 2001, at URL http://ssldata.nrcs.usda.gov/.
uark, University of Arkansas, 2000, unpublished data, Soil Characterization Laboratory, Fayetteville, AR, provided to USGS, 1999-2000.
uiuc, University of Illinois, 2001, Soil Characterization Database, Soil Characterization Laboratory, Urbana-Champaign, IL, accessed February 15, 2001, at URL http://www.il.nrcs.usda.gov/technical/soils/soil_lab.html.
2/ Soil Survey Staff, 1995, Soil survey laboratory information manual:  U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE, Soil Survey Investigations Report No 45, version 1, 305 p.
3/ Soil Survey Staff, 1996, Soil survey laboratory methods manual : U.S. Department of Agriculture, Natural Resources Conservation Service, Soil Survey Investigations Report No. 42, version 3, 693 p.
4/ Walkley A., 1935, An examination of methods for determination of organic carbon and nitrogen in soils:  Journal of Agricultural Science, v. 25, p. 598-609.
5/ Soil Survey Staff, 1998, Keys to soil taxonomy, 8th ed.: U.S. Department of Agriculture, Natural Resources Conservation Service, 328 p.
6/ U.S. Department of Agriculture, Natural Resources Conservation Service, 2001, State Soil Geographic (STATSGO) Database, accessed September 1, 2001, at URL http://www.ncgc.nrcs.usda.gov/branch/ssb/products/statsgo/index.html.
7/ U.S. Department of Agriculture, Natural Resources Conservation Service, 2001, Soil Survey Geographic (SSURGO) Database, accessed September 1, 2001, at URL http://www.ncgc.nrcs.usda.gov/branch/ssb/products/ssurgo/index.html.
8/ 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.