Agriculture Reference
In-Depth Information
(a)
(b)
(c)
(d)
b HS = 0, CEC = 0,
[X ] L
b HS = 15, CEC = 35,
[X ] L
b HS = 50, CEC = 35,
[X ] L
b HS = 50, CEC = 10,
[X ] L
=
0
=
20
=
20
=
10
4.0
18
8.0
16
Fe 2 +
3.5
7.5
Fe 2 +
14
Fe 2 +
3.0
7.0
pH
12
pH
pH
2.5
6.5
10
pH
2.0
8
6.0
Fe 2 +
6
1.5
5.5
4
1.0
5.0
2
pe
pe
0.5
O 2
4.5
pe
pe
0
O 2
O 2
O 2
0.0
2
4.0
0
2
4
6
8
10121416 0
2
4
6
8
10121416 0
2
4
6
8
10121416 0
2
4
6
8
10121416
CH 2 O oxidized (mmol kg 1 )
Figure 4.7 Calculated changes in pe, pH, [O 2 ]and[Fe 2 + ] in an idealized soil during reduction. Mineral phases Fe(OH) 3 and Fe 3 ( OH ) 8 .
Parameters for pH buffering and cation exchange differ between (a) - (d) as indicated. Units of b HS (soil pH buffer power), mmol kg 1
pH 1 ;
CEC (initial cation exchange capacity), cmol c kg 1 ;and[X ] L (concentration of non-carbonate anions), mM. CO 2 pressure
=
10 kPa,
θ =
0 . 6, ρ =
1 . 0, initial pH
=
4 . 5
Search WWH ::




Custom Search