Agriculture Reference
In-Depth Information
soil may contribute to land degradation and subsequent water pollution in vast areas, mostly in
the lesser-developed countries of tropical and subtropical regions. Phosphorus deficiency often
limits the growth of crops, and may even cause a crop failure, which forces farmers to clear
more land in order to survive. Without adequate phosphorus, regrowth of natural vegetation on
disturbed forest and savanna sites is often too slow to prevent soil erosion and depletion of SOM
(Fageria, 2002).
4.8.4 l
ImInG
a
CId
s
oIls
Acidic soils, which occupy 30-40% of agricultural land in the world, compromise plant growth and
have a negative impact on agriculture (Yamaguchi et al., 2004). Liming is one of the most effective
and dominant practices to reduce soil acidity (Fageria and Baligar, 2003b). Liming had many ben-
eficial effects on acid soils when it was applied in adequate amounts. It improves soil pH and base
saturation, neutralizes H
+
and Al
3+
ions toxicity, and improves the biological activity of beneficial
microorganisms. Liming also improves P uptake by crops grown on limed acid soils (Fageria, 1989;
Fageria and Baligar, 2003b). All these chemical changes create a favorable environment for plant
growth and improve the OM content of soils and bring sustainability of cropping systems. Data in
Table 4.6 show changes in soil chemical properties at two soil depths of a Brazilian Oxisol with lim-
ing under NT cropping system. The pH, base saturation, and Ca and Mg saturation increased sig-
nificantly with increasing lime rates at two soil depths. The H + Al and acidity saturation decreased
significantly with increasing lime rates at two soil depths.
TABLE 4.6
Selected Soil Chemical Properties after Harvest of Dry Bean
Crops at Two Soil Depths as Influenced by Liming Treatments
Lime Rate (Mg ha
−
1
)
Soil Property
0
12
24
F-Test
CV(%)
(0-10 cm Depth)
pH
5.4c
6.7b
7.1a
a
2
Base saturation (%)
27.9c
70.5b
84.3a
21
a
H + Al (cmol
c
kg
−1
)
7.0a
2.3b
1.2c
a
19
Acidity saturation (%)
7.2a
2.1b
1.6c
a
25
1.9c
3.9b
4.7a
10
Ca (cmol
c
kg
−1
)
a
0.5b
1.4a
1.4a
13
Mg (cmol
c
kg
−1
)
a
(10-20 cm Depth)
pH
5.3c
6.1b
6.5a
2
a
Base saturation (%)
24.6c
49.5b
62.8a
a
21
7.1a
4.4b
3.1c
a
14
H + Al (cmol
c
kg
−1
)
Acidity saturation (%)
7.6a
5.2b
3.7c
a
7
Ca (cmol
c
kg
−1
)
1.7c
2.9b
3.8a
a
15
0.4c
1.1b
1.3a
15
Mg (cmol
c
kg
−1
)
a
Source:
Adapted from Fageria, N. K., L. F. Stone, and A. Moreira. 2008.
J. Plant Nutr.
31:1723-1735. With permission.
Note:
Values are averages of three bean crops at harvest.
a
Significant at the 1% probability level. Means followed by the same letter in the same line
for the same parameter under different lime treatments are statistically not significant at
the 5% probability level by Tukey's test.
