Agriculture Reference
In-Depth Information
0.5
Calcareous Soil
Surface Layer
0.4
0.3
SOM
0.2
Linear
0.1
0.0
0
20
40
60
80
100
120
Calcareous Soil
Subsurface Layer
1.0
0.8
0.6
SOM
0.4
Linear
0.2
0.0
0
20
40
60
80
100
120
Pore Volume (V/V
o
)
FIGURE 6.25
Breakthrough results of Cu from surface soil (top) and subsurface soil (bottom). Solid curves are
simulations using the second-order model. Dashed curves represent linear model predictions.
used by Elbana and Selim (2012) is also described by Toride, Leij, and van
Genuchten (1995). This analytical model was utilized to solve the inverse
problem based on the assumption of linear equilibrium sorption and an
irreversible reaction to account for strong Cu sorption. The linear model
used, which incorporates a first-order decay (sink) term, is
2
∂
∂
C
t
∂
∂
C
z
∂
∂
C
z
R
=
D
−
v
−µ
C
(6.43)
2
where
R
is a dimensionless retardation factor (
R
=1 + ρ
K
d
/ϕ), and
K
d
is a par-
titioning coefficient (mL g
-1
). In Equation 6.44 the term
R
accounts for linear
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