Fig. 5. Comparison of apparent soil electrical conductivity (ECa) readings obtained with (left) Geonics EM38, (center) Veris 3100 shallow electrodes, and (right) Veris 3100 deep electrodes on Missouri field F1 (39°13'48'' N, 92°7'0'' W, Mexico and Adco soils). Within each map, an equal number of observations is contained in each classification interval.