Agriculture Reference
In-Depth Information
increase was 5.1-7.4 in the lime rate range of 0-18 Mg ha
−1
. The increase in pH with lime applica-
tion was associated with a neutralization of Al + H ions and an increase in Ca and Mg concentra-
tion in the soil solution. Fageria and Stone (2004) and Fageria (2006) reported a similar increase in
pH with the application of lime in the range of 0-24 Mg ha
−1
in the Brazilian Oxisol. Overall, the
increase in base saturation was 16.4-91.5%, H + Al decrease was 3.88-0.43 cmol
c
kg
−1
, Al decrease
was 1.52-0 cmol
c
kg
−1
, Ca increase was 0.45-3.14 cmol
c
kg
−1
, Mg increase was 0.19-1.32 cmol
c
kg
−1
,
and cation exchange capacity increase was 4.64-5.01 cmol
c
kg
−1
with the application of 0-18 Mg
lime ha
−1
. Fageria and Stone (2004) reported a similar increase or decrease in the acidity indices
of Brazilian Oxisol with the application of lime in the range of 0-24 Mg ha
−1
. Fageria (2001a) also
reported similar increases in Ca and Mg concentration Brazilian Oxisol with the application of lime
in the range of 0-20 Mg ha
−1
.
An interesting feature of these results is that, with the application of 3 Mg lime ha
−1
, practically
all the Al
3+
ions were neutralized. This means that acidity at a higher lime rate was represented by
H
+
ions in the soil solution. Fageria and Morais (1987) reported similar results with the application
of lime in the Brazilian Oxisol. Soil acidity indices (pH, Ca, Mg, base saturation, H + Al, acidity
saturation, Ca/K, and Mg/K) were having a significant quadratic association with grain yield (Table
3.19). The variability in grain yield was 93% due to soil pH, 96% due to the soil Ca content, 94%
due to the soil Mg content, 97% due to base saturation, 91% due to the H + Al content, 94% due to
acidity saturation, 89% due to the Ca/Mg ratio, 90% due to the Ca/K ratio, and 91% due to the Mg/K
ratio (Table 3.19). This means that the importance of acidity indices in increasing soybean yield was
in the order of base saturation > Ca > Mg > acidity saturation > pH > Mg/K > H + Al > Ca/K > Ca/
Mg. Fageria (2001b) reported a more or less similar importance of increasing soybean grain yield
in Brazilian Oxisol.
Values for maximum grain yield (3100 kg ha
−1
) calculated by quadratic regression equations were
7.1 for pH, 2.7 comol
c
kg
−1
for Ca, 1.6 comol
c
kg
−1
for Mg, 88% for base saturation, 0.49 comol
c
kg
−1
for H + Al, 5.2 cmol
c
kg
−1
for CEC, 1.92 Ca/Mg ratio, 9.5 Ca/K ratio, and 5.4 Mg/K ratio. Fageria
(2001b) reported that the maximum grain yield of soybean in Brazilian Oxisol was obtained with
63% base saturation and at a pH of 6.8. The Ca and Mg values for maximum grain yield of soybean
TABLE 3.19
Relationship between Soil Chemical Property (X) and Soybean Grain Yield
Soil Property
Regression Equation
R
2
VMY
a
VMEY
b
pH in H
2
O
Y = −9884.7040 + 3636.8190X − 254.6528X
2
0.9260**
7.1
6.0
Ca (comol
c
kg
−1
)
Y = 1484.3560 + 1189.5530X − 216.6682X
2
0.9577**
2.7
1.6
Mg (comol
c
kg
−1
)
Y = 1650.7640 + 1881.7360X − 584.0436X
2
0.9362**
1.6
0.9
Base saturation (%)
Y = 1397.4520 + 38.7096X − 0.2203X
2
0.9713**
88
51.0
H + Al (comol
c
kg
−1
)
Y = 3080.3400 + 93.4309X − 95.7709X
2
0.9076**
0.49
0
Acidity saturation (%)
Y = 3041.1380 + 11.3545X − 0.5417X
2
0.9409**
10.5
0
CEC (cmol
c
kg
−1
)
Y = −42,520.15 + 17,455.66X −1670.3430X
2
0.5101**
5.2
4.8
Ca/Mg ratio
Y = 5359.008 − 2288.174X + 281.131X
2
0.8903**
1.92
1.9
Ca/K ratio
Y = 1277.9740 + 397.1924X − 20.9609X
2
0.9006**
9.5
5.6
Mg/K
0.9124**
5.4
3.0
Y = 1599.9570 + 573.1361X − 52.9977X
2
Source:
From Fageria, N. K. et al. 2013b.
Commun. Soil Sci. Plant Anal
. 44: 2941-2951. With permission.
Note:
Values are averages of three crops.
a
VMY = value of maximum yield was calculated by a quadratic regression equation.
b
VMEY = value of maximum economic yield was calculated by a regression equation on the basis of 90% of the maximum
yield.
**Significant at the 1% probability level.