Agriculture Reference
In-Depth Information
Figures 6.15 and 6.16 give the profiles of Fe(II) and Fe(III) concentration
and pH measured by Begg
et al
. (1994) and Kirk and Bajita (1995). Blocks of
reduced soils were placed in contact with planar layers of rice roots, with the
roots separated from the soil by fine nylon mesh which they could not penetrate.
0.25
7.0
3 days
6.5
0.20
6.0
pH
0.15
5.5
0.10
Fe(III)
5.0
Fe(II)
0.05
4.5
0.00
4.0
0.25
7.0
5 days
6.5
0.20
6.0
0.15
5.5
0.10
5.0
0.05
4.5
0.00
4.0
0.25
7.0
10 days
6.5
0.20
6.0
0.15
5.5
0.10
5.0
0.05
4.5
0.00
4.0
0
2
4
6
8
10
12
Distance from root plane (mm)
Figure 6.15
Profiles of ferrous and ferric iron and pH in blocks of two reduced soils in
contact with planar layers of rice roots for indicated times in Iloilo soil. Iloilo soil is a
highly weathered sandy loam, org C
=
1
.
2%, aerobic pH
=
3
.
4, reducible Fe
=
80mmol
kg
−
1
(Begg
et al
., 1994). Reproduced by permission of Blackwell Publishing
