Agriculture Reference
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by the retarded transport for the reactive solute over time. Figure  3.6b
clearly illustrates the influence of different values of R on the movement
of a solute in the soil profile. For the nonlinear case (Equation 3.40), the
influence of retardation on the movement of a solute in soils having differ-
ent retardation Freundlich b values is presented in Figure 3.7. Figure 3.7a
shows a comparison of solute distribution for a linear case ( b = 1) and a
nonlinear case ( b = 0.5). Figure  3.7b shows a comparison of solute dis-
tribution for solutes having different values of b . For b < 1, the resulting
profile indicates excessive spreading, whereas for b > 1, the distribution is
presented by a sharp front in contrast to those where b equals 0.5 or 1. As
105
b = 1
100
b = 0.5
50
b = 1.5
0
0
20
40
60
80
Soil Depth z (cm)
75
b = 1.5
50
b = 0.5
25
b = 1
0
0
20
40
60
80
Soil Depth z (cm)
FIGURE 3.7
Solute concentration and the amount sorbed versus depth for different values of the Freundlich
parameter b . For linear sorption, b is 1.
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