Agriculture Reference
In-Depth Information
120
A 0.5
A 0.7
B 0.3
B 0.5
C 0.3
C 0.5
100
80
60
40
20
0
9.5
9.0
8.5
8.0
7.5
7.0
5
4
3
2
1
0
500
400
300
200
100
0
0
20
40
60
80
100
120
Time (h)
Figure 3.15
Precipitation of calcite in three soils (A, B, C) as pH increases during
hydrolysis of urea, and simultaneous changes in pH, P and dissolved organic C (DOC) in
the soil solution. Moist soil was incubated with CaCl
2
and urea at constant CO
2
pressure.
Numbers with symbols are initial concentrations of urea (M). Data of Huang (1990).
Reproduced by permission
