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Field-Scale Electrical Conductivity Mapping for Delineating Soil Condition

^a USDA-ARS, 120 Keim Hall, Lincoln, NE 68583-0934
^b Usda-Ars, Aerc-Csu, Ft. Collins, Co 80523-1325
^c Univ. of Nebraska, 103 Miller Hall, Lincoln, NE 68583

View larger version (115K): [in a new window]   Fig. 1. Experimental layout superimposed on the March 1999 ECa map of the 250-ha site. Field numbers, followed by cropping treatments winter wheat (W), corn (C), proso millet (M), and fallow (F), for the 1998 and 1999 (in parenthesis) growing seasons are shown in the upper left-hand corner of each field.

View larger version (150K): [in a new window]   Fig. 2. A gray-scale electrical conductivity map for field 1 (top) and the same map following recoding into four electrical conductivity classes (bottom). Variations in color, from dark to light, correspond to increasing conductivity, and "" symbols represent selected soil sampling sites.

View larger version (18K): [in a new window]   Fig. 3. Relationship between surface residue content and field-scale apparent electrical conductivity (ECa). Each point represents the mean of six samples. The error bars depict the standard errors of the mean.