Geoscience Reference
In-Depth Information
17
Mapping of Soil Drainage
Classes Using Topographical
Data and Soil Electrical
Conductivity
A. N. Kravchenko
ContentS
17.1 Introduction ......................................................................................................................... 255
17.2 Materials and Methods........................................................................................................ 256
17.2.1 Soil and Topographical Data ................................................................................. 256
17.2.2 Discriminant Analysis and Geostatistical Procedures .......................................... 257
17.3 Results and Discussion........................................................................................................ 258
17.4 Conclusions ......................................................................................................................... 260
R e f e r e n c e s ...................................................................................................................................... 260
17.1 IntRodUCtIon
Soil drainage is an important soil property affecting plant growth, water flow, and solute transport
in soils. Accurate and inexpensive prediction and mapping of soil drainage classes for agricul-
tural fields or small watersheds are of great importance for both agricultural and environmental
management. However, accurate drainage mapping of a particular site is often not possible without
taking soil cores—a task that is both time consuming and expensive. Therefore, it would be benefi-
cial to determine other easily measured factors for quantitative prediction of soil drainage on small
scales and to estimate potential accuracy of such prediction.
Topography is one of the easily evaluated drainage affecting factors that can greatly facilitate
mapping and prediction of soil drainage (Bell et al., 1992, 1994; Troeh, 1964). Another easily mea-
sured factor potentially related to drainage is soil electrical conductivity (EC). It can be measured
in the field using recently developed fast and nondestructive methods (Doolittle et al., 1994; Kitchen
et al., 1999). Electrical conductivity depends on a number of soil physical properties, including soil
salinity, soil water, and clay content (Rhoades et al., 1989). Sheets and Hendrickx (1995) found a
linear relationship between the electrical conductivity measurements and soil profile water content.
Williams and Hoey (1987) observed positive correlations between conductivity and soil clay con-
tent. Because both soil profile water contents and clay contents are related to the soil drainage prop-
erties, it would be reasonable to expect that electrical conductivity data might be helpful in mapping
and predicting soil drainage classes on a field-scale basis.
The objectives of this study were (1) to examine the relationships between soil drainage and
various topographical factors and to determine the factors that can be most helpful in predicting soil
drainage classes on a field scale using the results from a farm field in Central Illinois, (2) to study
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