Geoscience Reference
In-Depth Information
13
Relations between a
Commercial Soil Survey
Map Based on Soil Apparent
Electrical Conductivity
(EC
a
) and Measured Soil
Properties on a Morainic
Soil in Southeast Norway
Audun Korsaeth, Hugh Riley, Sigrun H. Kværnø, and
Live S. Vestgarden
ContentS
13.1 Introduction ......................................................................................................................... 225
13.2 Material and Methods ......................................................................................................... 226
13.2.1 Location................................................................................................................. 226
13.2.2 EM-EC
a
Device ..................................................................................................... 227
13.2.3 Measurements........................................................................................................ 227
13.2.4 Statistics and Data Analyses.................................................................................. 227
13.3 Results ................................................................................................................................. 227
13.4 Discussion ........................................................................................................................... 229
13.5 Conclusions ......................................................................................................................... 230
References ...................................................................................................................................... 231
13.1 IntRodUCtIon
The use of noninvasive electromagnetic (EM) induction to measure apparent profile soil electri-
cal conductivity (EC
a
) provides a time- and cost-effective tool to map within-field variation in soil
properties. Apparent electrical conductivity (EC
a
) shows the depth-weighed summarized effect of
all factors influencing EC in soil, and a range of chemical and physical properties have been indi-
rectly determined by the EM-EC
a
method, such as soil salinity hazard (Williams and Baker, 1982),
soil water content (Sheets and Hendrickx, 1995), claypan thickness (Doolittle et al., 1994), topsoil
inorganic N content (Korsaeth, 2005a), and nutrient levels (Heiniger et al., 2003).
Soil mapping based on the EM-EC
a
technique is offered commercially in many countries, such
as New Zealand (www.nzcpa.com), Denmark (www.gpsagro.dk), Sweden (www.analycen.se), and
225
