Sodium‐Affected Soil Identification in South‐Central Illinois by Electromagnetic Induction

Abstract

The irregular shape, small size, and spotty occurrence of sodium‐affected soils (NaAS) in moderately thick to thin loess over Illinoian till have continued to slow mapping in south‐central Illinois. Use of a Geonics EM‐38 ground conductivity meter to recognize soils with natric horizons in Tennessee suggested that this device would be useful in Illinois. We selected eight areas of NaAS in five counties of south‐central Illinois to find if the EM‐38 would be useful for predicting exchangeable sodium percentage (ESP). Approximately 225 observation points, spaced at 10‐m intervals, were established in each area and 107 sample cores were collected for laboratory analyses. Weighted averages of the ESP, electrical conductivity of the saturation extract from a saturated soil paste (ECe), and field pH data for 0 to 75‐ and 75 to 150‐cm depths were compared with the horizontal (EMh) and vertical (EMv) responses and the mean ESP data increases with depth, i.e., 7.0 at 35 cm, 9.7 at 75 cm, and 12.5 at 135 cm. The EMh readings correlate almost as well with ESP (r = 0.73) as with ECe (r = 0.76) for the 0‐ to 75‐cm depths. The EMv readings correlate slightly better with ESP (r = 0.76) than with ECe (r = 0.68) for the 75‐ to 150‐cm depth. These results show that EM readings may by used to predict ESP. The correlations of the depth‐weighted average ESP at the maximum depth for meeting natric horizon criteria in these soils (75 cm), and the EMv readings show that the EM‐38 provides a rapid and accurate method to describe the composition of the map units of NaAS on moderately thick to thin loess over Illinoian till in south‐central Illinois.

Spatial Relation of Apparent Soil Electrical Conductivity with Crop Yields and Soil Properties at Different Topographic Positions in a Small Agricultural Watershed

“…Electromagnetic techniques have been well noted for mapping of salt-affected soils [60]. Salts of Na can be an important contributor to salinity in southern and central Illinois and electromagnetic induction techniques have been widely used in mapping these salt affected soils [61][62][63][64] and a moderate to strong correlation was observed at our research site.…”

“…Splitting data on soil topographic position results in changing correlation among datasets. This can be explained by the change in spatial resolution of the data set where modifiable areal unit problem (MUAP) can occur [63,65,66]. Modeling Mehlich-3 P data splitting on basis of topographic positions can improve correlation and spatial interpolation while reducing cross validation RMSE.…”

The use of electromagnetic induction techniques in soils studies

“…The aforementioned relationships have been used to map saline-and sodic-soils (Ammons et al, 1989;Doolittle et al, 2001;Ganjegunte and Braun, 2011;Heilig et al, 2011;Lesch et al, 1992;Nettleton et al, 1994;Thomas et al, 2009) and recharge and discharge areas (Hopkins and Richardson, 1999;Sherlock and McDonnell, 2003;Williams and Arunin, 1990). Fig.…”

Nondestructive assessment of rangeland soil depth to petrocalcic horizon using electromagnetic induction

“…Although electromagnetic induction has been used to map a variety of soil properties and soil types (e.g., deJong et al, 1979;Williams & Hoey, 1987;Kachanoski et al, 1988;McBride et al, 1990;Slavich & Petterson, 1990;Diaz & Herrero, 1992;Doolittle et al, 1994;Nettleton et al, 1994;Lesch et al, 1995aLesch et al, , 1995bSheets & Hendrickx, 1995;Kitchen et al, 1996), the study described here is the first to address the utility of this tech- Figure 6. Scatterplot of actual soil depth versus soil depth predicted by apparent conductivity measured with the EM38 in the horizontal dipole orientation (n = 15).…”

“…Electromagnetic induction has been most extensively used to detect, map, and monitor soil salinity (deJong et al, 1979;Rhoades & Corwin, 1981;Williams & Baker, 1982;Corwin & Rhoades, 1982, 1990Wollenhaumpt et al, 1986;Rhoades et al, 1990;Slavich, 1990;Slavich & Petterson, 1990;Cook & Walker, 1992;Diaz & Herrero, 1992;Lesen et al, 1993;Cannon et al, 1994;Lesen et al, 1995aLesen et al, , 1995b. It has also been used to map soil water content (Kachanoski et al, 1988;Sheets & Hendrickx, 1995), sodic soils (Ammons et al, 1989;Nettleton et al, 1994), depth to claypans (Sudduth & Kitchen, 1993;Doolittle et al, 1994), salt and clay content (Williams & Hoey, 1987), presence of and depth to clay lamellae, buried soils, and water Downloaded by [University of New Mexico] at 18:34 13 October 2014 tables (Doolittle et al, 1996), forest soil properties important to biomass production (McBride et al, 1990), and depth of sand deposited from floodwaters (Kitchen et al, 1996).…”