Agriculture Reference
In-Depth Information
Table 3.8.4.
Crop management system and rotation effects on aggregate stability.
Aggregate stability (%)
1993
1995
1997
Soil depth (cm)
0-7
7-30
0-30
0-7
7-30
0-30
0-7
7-30
0-30
Mean effects
CS
58.0
56.5
56.8
54.6
52.9
53.7
60.7
55.9
57.0
LIS
57.4
55.6
56.0
54.7
54.5
54.5
58.6
56.8
57.2
Rot. 1
58.7
52.3
53.8
b
50.3
b
50.2
b
50.2
b
b
55.1
b
b
53.7
b
b
54.0
b
ab
58.9
ab
ab
57.0
ab
b
57.4
b
Rot. 2
58.9
57.9
58.1
52.8
54.6
54.1
Rot. 3
55.6
57.8
57.3
a
63.6
a
56.4
a
58.1
a
a
65.0
a
a
58.4
a
a
60.0
a
Interactions
CS
×
Rot. 1
60.0
53.2
54.8
49.6
47.9
48.3
56.9
54.6
55.1
CS
×
Rot. 2
58.8
59.0
58.9
55.0
55.8
55.6
60.1
57.5
58.1
CS
×
Rot. 3
55.2
57.2
56.7
64.6
55.1
57.3
65.3
55.7
57.9
LIS
Rot. 1
57.4
51.5
52.9
50.9
52.5
52.1
53.4
52.8
52.9
×
LIS
×
Rot. 2
59.0
56.8
57.3
50.7
53.3
52.7
57.6
56.5
56.8
LIS
×
Rot. 3
55.9
58.4
57.8
62.7
57.6
58.8
64.7
61.2
62.0
Year
57.7
56.0
56.4
54.6
53.7
54.1
59.7
56.4
57.1
Values followed by the same letter in the same column are not statistically different at the 0.05
probability level.
Fig. 3.8.2.
Aggregate
stability: 'year
×
rotation'
interaction.
Adoption of LIS preserved soil total N content both in the upper
(1.19‰ in 1993 and 1.27‰ in 1997) and lower layers (0.96 and 0.93‰,
respectively) (Fig. 3.8.3a and 3.8.3b) and, consequently, in the combined
layer. In contrast, a significant decrease was observed in both layers under
CS (from 1.12 to 0.74‰ in the 0-7 cm layer and from 0.92 to 0.74‰ in the
7-30 cm layer). The effect of crop management systems on assimilable
P
2
O
5
was significant only in the upper soil layer in 1997 (as mean effect)
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