Geoscience Reference
In-Depth Information
tAble 12.3
Correlation Coefficients between Selected Soil properties at three
depths and Apparent Soil electrical Conductivity (log-transformed),
Measured in Autumn 2001 at Møystad (n = 16) Using eM38
in either horizontal (eM
h
) or vertical (eM
v
) Modes
depth (cm)
0-20
20-40
40-60
Soil
property
log eM
h
log eM
v
log eM
h
log eM
v
log eM
h
log eM
v
Gravel
a
−0.54*
n.s.
−0.60*
n.s.
n.s.
n.s.
Coarse sand
−0.53*
−0.56*
n.s.
n.s.
n.s.
n.s.
Middle sand
−0.52*
n.s.
n.s.
n.s.
n.s.
n.s.
Fine sand
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
Total sand
a
−0.73**
−0.57*
−0.53*
−0.60*
n.s.
−0.64**
Coarse silt
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
Middle silt
n.s.
n.s.
n.s.
n.s.
n.s.
0.52*
Fine silt
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
Total silt
a
n.s.
n.s.
n.s.
n.s.
n.s.
0.56*
Clay
a
0.83***
0.75**
0.77**
0.74**
0.62*
0.67**
Ignition loss
0.49*
n.s.
0.69**
n.s.
0.62*
0.67**
Note:
*
p
< 0.05; **
p
< 0.01; ***
p
< 0.001, n.s. not significant.
a
Particle size of gravel: >2000 μm, total sand: 60 to 2000 μm, total silt: 2 to 60 μm and clay:
<2 μm.
tAble 12.4
Regression Models from Stepwise Regression Analyses,
which Included only Significant Constants and predictors
a
;
dependent variable is log-transformed eM
h
, and Adjusted
Coefficients of determination (r
2
adj
) Are Shown
Regression equations
r
2
adj
Apelsvoll
log EM
H
= 0.426 + 0.018 Cl
0-20
0.572
log EM
H
= 0.453 + 0.016 Cl
0-20
+ 0.007 FSa
60-80
− 0.006 MSa
30-50
0.724
Møystad
log EM
H
= 1.597 + 0.015 Cl
0-20
0.666
log EM
H
= 1.590 + 0.012 Cl
0-20
+ 0.011 IGL
20-40
0.736
log EM
H
= 1.706 + 0.027 IGL
20-40
− 0.011 MSi
20-40
− 0.011 CSa
40-60
+
0.019 CSi
0-20
− 0.002 FSa
40-60
0.887
a
Predictors: Cl, clay; FSa, fine sand; MSa, medium sand; CSa, coarse sand; MSi,
medium silt; CSi, coarse silt; IGL, ignition loss. Subscripts indicate depths in
centimeters.
content was included as predictor in four of the five regression models resulting from the stepwise
procedure. An interpolated map of measured EM
H
at the Apelsvoll location is shown in Figure 12.1.
The variation in EM
H
within the field was reasonably well represented by the measurement points,
