Agriculture Reference
In-Depth Information
Average of two soil depths
3000
2000
Y = -19,976.52 + 7100.26X - 544.61X
2
R
2
= 0.8015**
1000
0
10-20 cm
3000
2000
Y = -24,558.65 + 8834.69X - 703.87X
2
R
2
= 0.7704**
1000
0
0-10 cm
3000
2000
Y = -18,901.84 + 6616.88X - 495.48
2
R
2
= 0.8233**
1000
0
5.0
5.5
6.0
6.5
7.0
7.5
Soil pH in H
2
O
FIGURE 8.2
Relationship between soil pH and grain yield of dry bean. (From Fageria, N. K. 2008.
Commun.
Soil Sci. Plant Anal.
39:845-857. With permission.)
(negatively charged particles of clay or organic matter), forming
HCO
3
−
. In the second step,
HCO
3
−
reacts with H
+
to form CO
2
and H
2
O to increase pH. The liming reaction rate is mainly determined
by the soil moisture and temperature and quantity and quality of liming material. To get maximum
benefits from liming or for improving crop yields, liming materials should be applied in advance of
crop sowing and thoroughly mixed into the soil. Selected soil chemical property changes with lime
applied to a Brazilian Oxisol are presented in Tables 8.2 and 8.3.
The quantity of lime required for specific crops can be determined by laboratory methods
(Adams, 1984; Fageria and Baligar, 2003b). However, the best method for lime quantity determi-
nation for a given crop is crop yield versus lime rate curves (Fageria and Baligar, 2005). Some of
the curves developed for the dry bean, soybean, and corn in a Brazilian Oxisol are presented and
discussed by Fageria (2001) and Fageria and Baligar (2005). The author developed a lime response
curve for soybean grown on a Brazilian Oxisol (Figure 8.7). The maximum grain yield of soybean
was obtained with the addition of 12.6 Mg dolomitic lime per hectare. In tropical America, the
quantity of lime required is calculated by taking into account Al, Ca, and Mg according to the fol-
lowing equation (Fageria et al., 1990):
Lime rate (Mg ha
−1
) = (2 × Al) + {2 − (Ca + Mg)}
where Al, Ca, and Mg are in cmol
c
kg
−1
soil.
