EVALUATING GPR AND EMI FOR MORPHOLOGICAL STUDIES OF LOESSIAL SOILSInman, Daniel J.1; Freeland, Robert S.2; Yoder, Ronald E.2; Ammons, John T.1; Leonard, L. Leroy2Soil Science: September 2001 - Volume 166 - Issue 9 - pp 622-630 Article Abstract Author Information Development of a rapid and nonintrusive method for obtaining accurate soil morphological information is critical for pinpointing areas that are prone to leaching. The purpose of this study was to evaluate the suitability of using ground-penetrating radar (GPR) and electromagnetic induction (EMI) techniques in combination to gather soil morphological information on loessial soils. A survey of apparent electrical conductivity (ECa) was conducted in southwestern Tennessee at 10-m increments throughout a 1-ha field. Based on variation in the EMI data, a 36-m transect was selected for further investigation by GPR using a 200-MHz antenna. A hydraulic excavator was used to trench the site to a depth of 3 m, and a complete soil morphological investigation was performed along the trench face at 6-m increments. Readings from the EMI showed a moderate correlation with percent fragic properties (r = 0.40). Average depth to the loess/alluvium interface interpreted from the GPR was 1.20 m, and to the alluvium/Tertiary sand interface, 1.88 m. The loess/alluvium and alluvium/Tertiary sand interfaces interpreted from the GPR data had strong relationships to the measured depths, R2 = 0.90 and 0.88, respectively. Results from this study show that using precursory EMI data to pinpoint GPR surveys is a precise, accurate, and rapid means of acquiring field-scale soil morphological information. 1Plant and Soil Sciences Department, The University of Tennessee, P.O. Box 1071, Knoxville, TN 37901-1071. Dr. Ammons is corresponding author. E-mail:firstname.lastname@example.org 2Agricultural and Biosystems Engineering Department, The University of Tennessee, Knoxville, TN. Received Feb. 6, 2001; accepted May 17, 2001. © 2001 Lippincott Williams & Wilkins, Inc.