HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Shirazi, M. A. Articles by Johnson, C. B. Search for Related Content PubMed PubMed Citation Articles by Shirazi, M. A. Articles by Johnson, C. B. GeoRef GeoRef Citation Agricola Articles by Shirazi, M. A. Articles by Johnson, C. B. Related Collections Water Quality Watershed and Landscape Processes Soil Models

TECHNICAL REPORT
LANDSCAPE AND WATERSHED PROCESSES

Spatial Extrapolation of Soil Characteristics Using Whole-Soil Particle Size Distributions

^a Western Ecology Division, NHEERL, U.S. Environmental Protection Agency, 200 S.W. 35th Street, Corvallis, OR 97333
^b OAO Corporation, 200 S.W. 35th Street, Corvallis, OR 97333

Corresponding author (safa{at}mail.cor.epa.gov)

Received for publication February 22, 2000. Soils support ecosystem functions such as plant growth and water quality because of certain physical, chemical, and biological properties. These properties have been studied at different spatial scales, including point scales to satisfy basic research needs, and regional scales to satisfy monitoring needs. Recently, soil property data for the entire USA have become available in the State Soil Geographic Data Base (STATSGO), which is appropriate for regional-scale research. We analyzed and created models of STATSGO data in this study to serve as a research tool, for example, for linking the soil to regional water quality monitoring data in our companion paper. Map units in STATSGO define geographic land areas by soil characteristics (SCs) of similar soil series. We selected 27 SCs that influenced water properties (in varying degrees), aggregated the layer and component SCs to map unit SCs, and used SCs to calculate relationships among map units. The relationships were defined by equations of conditional mean for the q^th SC (SCq), while using the remaining 26 SCs as predictors. The relative standard errors for 22 of the 27 SCs were less than 10%, and less than 22% for the remaining five. We conclude that spatial extrapolation of SCs is feasible and the procedures are a first step toward extrapolating information across a region using SC–water property relationships. Although our procedure is for regional scale monitoring, it is also applicable to finer spatial scales commensurate with available soil data.

Abbreviations: g, geometric particle standard deviation • CEC, cation exchange capacity • comppct, component percent • cr, coarse-textured soils • cstdv, conditional standard deviation • dg, geometric mean particle diameter • fn, fine-textured soils • ir, index of relationship of a soil characteristic of a map unit • mecr, medium coarse-textured soils • mocr, moderately coarse-textured soils • mofn, moderately fine-textured soils • MUG, map unit group • MUID, map unit identification code • PSD, particle size distribution • SC, soil characteristic • STATSGO, State Soil Geographic Data Base • stdv, standard deviation • USDA12, conventional USDA texture classes • USDA5, aggregated USDA texture classes

This article has been cited by other articles:

				M. A. Shirazi, C. B. Johnson, J. M. Omernik, D. White, P. K. Haggerty, and G. E. Griffith Quantitative Soil Descriptions for Ecoregions of the United States J. Environ. Qual., March 1, 2003; 32(2): 550 - 561. [Abstract] [Full Text] [PDF]

				M. A. Shirazi, L. Boersma, C. B. Johnson, and P. K. Haggerty Predicting Physical and Chemical Water Properties from Relationships with Watershed Soil Characteristics J. Environ. Qual., January 1, 2001; 30(1): 112 - 120. [Abstract] [Full Text]