Agriculture Reference
In-Depth Information
500
Windsor
400
300
200
Initial Zn = 60 ppm
Initial Zn = 80 ppm
Initial Zn = 100 ppm
Sorption
Sorption simulated
Desorption simulated
100
Zn-Hysteresis (P = 0)
0
0
10
20
30
40
50
60
600
Windsor
500
400
300
Initial Zn = 60 ppm
Initial Zn = 80 ppm
Initial Zn = 100 ppm
Sorption
Sorption simulated
Desorption simulated
200
100
Zn-Hysteresis (P = 100)
0
0
10
20
30
40
50
Zn Concentration (mg/L)
FIGURE 7.23
Adsorption and desorption isotherms for Windsor soil with different P concentration. The
solid and dashed curves depict results of multireaction (MRM) model simulations for sorption
and desorption.
In order to assess the mobility of Zn in soils, column transport experiments
were carried out using the miscible displacement technique. Transport of
Zn in soils was quantified using miscible displacement techniques in water-
saturated soil columns. A Zn pulse solution with or without P was applied to
each column. In Figure 7.25, Zn BTCs are presented for a Windsor soil column
that received a pulse of Zn alone (column 1). In contrast, in Figure 7.26, results
show BTCs where a mixed pulse of P and Zn was introduced (column 2).
A comparison of the two Zn BTCs clearly shows increased retention of Zn
sorption in the presence of P (see Figure  7.27). In fact after some 120 pore
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