Table 2.4 Importance ranking of potential predictors for RSGs using the random forest approach (mean decrease in accuracy of the method; importance
increases with the value)
AC
AL
AT
CH
CM
FL
FR
GL
LP
LV
LX
RG
ST
TC
UM
W
K
1.9
1.5
2.2
À1.8
0.2
5.3
1.0
1.8
2.1
3.8
0
3.9
0
À3.1
2.1
6.1
eTh
1.8
1.5
À0.6
1.4
1.0
4.0
À2.0
À1.2
2.0
5.6
0
4.2
0
5.5
2.8
5.8
eU
2.0
1.4
À1.5
À1.0
À0.6
3.1
1.0
1.8
1.8
4.0
0
3.4
0
3.4
0.8
5.2
dem
1.9
1.6
À1.0
0.8
1.0
4.9
1.4
À0.2
1.2
5.1
0
3.7
0
4.7
1.7
4.7
asp.
0.4
0.5
À0.4
À1.7
0.6
1.9
À1.0
0.2
0.7
5.4
0
2.6
0
0.8
0.6
À2.9
curv
1.3
1.2
0.3
1.2
À0.3
4.3
À1.0
À0.6
0.8
0.8
0
4.1
0
À0.5
À1.3
3.4
cv
1.3
0.9
À2.1
0
À0.0
1.9
À2.3
À2.1
1.6
0.5
0
2.5
0
0.3
0.4
1.3
plc
1.1
1.0
À0.2
0.6
0.1
2.0
À1.7
À1.1
2.0
0.3
0
2.6
0
À0.6
À0.1
0.5
prc
1.0
0.9
1.5
0
À0.0
3.2
À0.6
À1.0
0.5
0.4
0
2.7
0
1.9
À0.1
0.5
tri
0.8
1.1
À1.0
À0.3
0.2
1.0
À1.0
À0.5
1.4
2.0
0
2.2
0
5.7
1.4
4.7
vdcn
1.4
1.3
0
À2.0
0.5
3.9
1.4
0.2
1.4
4.3
0
2.6
0
1.7
1.5
2.8
wi
1.2
1.3
2.0
À2.3
0.5
1.2
0
À0.6
1.9
4.0
0
4.1
0
5.0
0.6
4.0
slope
0.9
1.1
À1.9
À1.6
0.3
0.8
À2.7
0.5
1.4
1.1
0
2.9
0
5.1
1.4
3.8
Ra
1.7
1.4
À0.2
1.0
0.3
4.7
0
À1.1
1.4
2.4
0
3.8
0
4.4
2.1
3.5
pm
1.7
1.1
1.2
0
À0.3
3.2
0
1.9
1.8
4.2
0
3.7
0
1.6
2.4
1.6
AC Acrisols,
AL Alisols,
AT Anthrosols,
CH Chernozems,
CM Cambisols,
FL Fluvisols,
FR Ferralsols,
GL Gleysols,
LP Leptosols,
LV Luvisols,
LX Lixisols,
RG Regosols,
ST Stagnosols,
TC Technosols,
UM Umbrisols,
W Waterbodies,
K potassium,
eTh thorium equivalent,
eU uranium equivalent,
dem altitude
above sea level,
asp aspect,
cur curvature,
cv convergence index,
plc plan curvature,
prc profile curvature,
tri terrain roughness index,
vdnc vertical distance to
channel network,
wi SAGA wetness index,
ra relative altitude,
pm parent material
2 Beyond the Horizons: Challenges and Prospects for Soil Science and Soil. . .
63
increases with the value)
AC
AL
AT
CH
CM
FL
FR
GL
LP
LV
LX
RG
ST
TC
UM
W
K
1.9
1.5
2.2
À1.8
0.2
5.3
1.0
1.8
2.1
3.8
0
3.9
0
À3.1
2.1
6.1
eTh
1.8
1.5
À0.6
1.4
1.0
4.0
À2.0
À1.2
2.0
5.6
0
4.2
0
5.5
2.8
5.8
eU
2.0
1.4
À1.5
À1.0
À0.6
3.1
1.0
1.8
1.8
4.0
0
3.4
0
3.4
0.8
5.2
dem
1.9
1.6
À1.0
0.8
1.0
4.9
1.4
À0.2
1.2
5.1
0
3.7
0
4.7
1.7
4.7
asp.
0.4
0.5
À0.4
À1.7
0.6
1.9
À1.0
0.2
0.7
5.4
0
2.6
0
0.8
0.6
À2.9
curv
1.3
1.2
0.3
1.2
À0.3
4.3
À1.0
À0.6
0.8
0.8
0
4.1
0
À0.5
À1.3
3.4
cv
1.3
0.9
À2.1
0
À0.0
1.9
À2.3
À2.1
1.6
0.5
0
2.5
0
0.3
0.4
1.3
plc
1.1
1.0
À0.2
0.6
0.1
2.0
À1.7
À1.1
2.0
0.3
0
2.6
0
À0.6
À0.1
0.5
prc
1.0
0.9
1.5
0
À0.0
3.2
À0.6
À1.0
0.5
0.4
0
2.7
0
1.9
À0.1
0.5
tri
0.8
1.1
À1.0
À0.3
0.2
1.0
À1.0
À0.5
1.4
2.0
0
2.2
0
5.7
1.4
4.7
vdcn
1.4
1.3
0
À2.0
0.5
3.9
1.4
0.2
1.4
4.3
0
2.6
0
1.7
1.5
2.8
wi
1.2
1.3
2.0
À2.3
0.5
1.2
0
À0.6
1.9
4.0
0
4.1
0
5.0
0.6
4.0
slope
0.9
1.1
À1.9
À1.6
0.3
0.8
À2.7
0.5
1.4
1.1
0
2.9
0
5.1
1.4
3.8
Ra
1.7
1.4
À0.2
1.0
0.3
4.7
0
À1.1
1.4
2.4
0
3.8
0
4.4
2.1
3.5
pm
1.7
1.1
1.2
0
À0.3
3.2
0
1.9
1.8
4.2
0
3.7
0
1.6
2.4
1.6
AC Acrisols,
AL Alisols,
AT Anthrosols,
CH Chernozems,
CM Cambisols,
FL Fluvisols,
FR Ferralsols,
GL Gleysols,
LP Leptosols,
LV Luvisols,
LX Lixisols,
RG Regosols,
ST Stagnosols,
TC Technosols,
UM Umbrisols,
W Waterbodies,
K potassium,
eTh thorium equivalent,
eU uranium equivalent,
dem altitude
above sea level,
asp aspect,
cur curvature,
cv convergence index,
plc plan curvature,
prc profile curvature,
tri terrain roughness index,
vdnc vertical distance to
channel network,
wi SAGA wetness index,
ra relative altitude,
pm parent material
2 Beyond the Horizons: Challenges and Prospects for Soil Science and Soil. . .
63