Geoscience Reference
In-Depth Information
12
Dependence of Soil Apparent
Electrical Conductivity (EC
a
)
upon Soil Texture and Ignition
Loss at Various Depths in
Two Morainic Loam Soils
in Southeast Norway
Audun Korsaeth
ContentS
12.1 Introduction ......................................................................................................................... 217
12.2 Material and Methods ......................................................................................................... 218
12.2.1 Locations ............................................................................................................... 218
12.2.2 EM-EC
a
Device ..................................................................................................... 218
12.2.3 Measurements........................................................................................................ 219
12.2.4 Data Analysis and Statistics .................................................................................. 219
12.3 Results ................................................................................................................................. 220
12.4 Discussion ........................................................................................................................... 222
12.5 Conclusions ......................................................................................................................... 222
References ...................................................................................................................................... 222
12.1 IntRodUCtIon
The use of sensor techniques provides a time- and cost-effective alternative to traditional soil sam-
pling and laboratory analyses, in order to monitor spatial and temporal soil variation. One sensor-
based, noninvasive technique is to measure apparent electrical conductivity (EC
a
) of a soil profile
by means of an electromagnetic (EM) induction approach. The device selected for the EM mea-
surements in this paper was the Geonics EM38 (Mississauga, ON, Canada; www.geonics.com),
which is the EM-EC
a
sensor most often used in agriculture (Sudduth et al., 2001). The device may
be operated in one of two measurement modes that give an effective measuring depth of either 0.75
or 1.5 m.
EM-EC
a
has been used successfully as an indirect indicator of important soil physical and
chemical properties, such as soil salinity hazard (Williams and Baker, 1982), soil water content
(Khakural et al., 1998), and topsoil inorganic N content (Korsaeth, 2005). Whereas these studies
focus mainly on soil variation in the lateral plane, others have used the EM-EC
a
technique with
217
