Geoscience Reference
In-Depth Information
19
Four-Year Summary of the
Use of Soil Conductivity
as a Measure of Soil
and Crop Status
Roger A. Eigenberg, John A. Nienaber, Bryan L. Woodbury,
and Richard B. Ferguson
ContentS
19.1 Introduction ......................................................................................................................... 273
19.2 Methods............................................................................................................................... 274
19.2.1 Site Description ..................................................................................................... 274
19.2.2 Field Operations on the Research Cornfield 274
19.2.3 Equipment.............................................................................................................. 274
19.3 Results and Discussion........................................................................................................ 275
19.3.1 EC a Maps and Plots ............................................................................................... 275
19.3.1.1 Main Plot—Cover Crop ........................................................................ 276
19.3.1.2 Subplot—Organic and Commercial Amendments ............................... 276
19.3.2 Statistical Analysis ................................................................................................ 277
19.3.2.1 Main Plots—Cover Crop....................................................................... 277
19.3.2.2 No-Cover, All Treatments ..................................................................... 278
19.4 Conclusions ......................................................................................................................... 278
References ...................................................................................................................................... 280
19.1 IntRodUCtIon
Sustainable agriculture requires innovative and practical tools to optimize farm economics, conserve
soil organic matter, and minimize negative environmental impacts (Johnson et al., 2003). Electro-
magnetic induction soil conductivity sensors may provide one such tool. Electromagnetic tech-
niques are well suited for mapping soil conductivity to depths useful for agriculturalists (McNeill,
1990). Electrical conductivity (EC) methods have been shown to be sensitive to high nutrient levels
(Eigenberg et al., 1996, 2000) and have been used to detect ionic concentrations on or near the soil
surface resulting from field application of cattle feedlot manure. EC has generally been associated
with determining soil salinity; however, EC also can serve as a measure of soluble nutrients (Smith
and Doran, 1996) for both cations and anions, and is useful in monitoring the mineralization of
organic matter in soil (De Neve et al., 2000). Doran et al. (1996) demonstrated the predictive capa-
bility of soil conductivity to estimate soil nitrate.
The objective of this work was to determine the utility of electromagnetic induction (EMI) meth-
ods in evaluating the agronomic effectiveness and environmental consequences of N fertilization
273
 
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