Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake
Table 1
Soil phosphorus determined by the resin method (P-res) and by the remainder method (P-rem) at depths of 0.0–0.2 m and 0.2–0.4 m, leaf phosphorus at four months (P-4) and at eight months (P-8) after sprouting, and acid phosphatase activity (APase) and juice phosphorus (P-juice) of sugarcane grown in Eutrophic Red Ultisol, as a function of phosphate fertilization with source, application rate, and filter cake.
P-res 0.0–0.2
P-res 0.2–0.4
P-rem 0.0–0.2
P-rem 0.2–0.4
P-4
P-8
APase
P-juice
mg dm−3
g kg−1
nmol min−1 mg−1
mg L−1
P sources
Araxa
47
20ab
30
19
1.4b
1.7
2340.9
47.8
Bayovar
45
18b
29
19
1.5b
1.7
2309.5
47.9
Triple superphosphate
57
25a
30
18
1.6a
1.7
2284.0
49.3
P2O5 rates
0
15
8
27
19
1.4
1.6
2346.7
37.0
90
35
18
30
19
1.5
1.7
2402.7
48.9
180
53
24
30
18
1.6
1.7
2324.4
53.2
360
99
33
32
19
1.7
1.8
2172.6
53.7
Filter cake
Presence
63
24
31
19
1.7
1.8
2079.5
49.5
Absence
37
18
29
19
1.4
1.6
2543.4
47.2
test
Source
3.0ns
4.2
0.1ns
0.2ns
9.8
0.2ns
0.4ns
0.4ns
Rate
101.3
26.3
10.0
0.6ns
14.6
4.7
3.3
22.5
Filter cake
54.6
8.3
3.9ns
2.0ns
81.0
62.3
73.2
2.1ns
Source × rate
2.1ns
1.4ns
0.1ns
0.9ns
2.2ns
1.2ns
1.5ns
0.4ns
Source × cake
4.7
0.2ns
0.1ns
0.1ns
1.3ns
0.6ns
7.1
0.2ns
Rate × cake
4.5
1.0ns
0.2ns
0.4ns
2.7ns
0.9ns
16.6
0.4ns
Source × rate × cake
1.0ns
0.7ns
0.1ns
1.1ns
2.2ns
0.9ns
2.3ns
0.1ns
CV, %
29.9
40.4
10.6
6.5
8.9
4.7
10.0
13.7
Averages followed by single letters are significantly different from other averages in the same column (Tukey test, ). , and ns: significant (, ) and insignificant ( test).