Agriculture Reference
In-Depth Information
numberof pods pot
numberofplants pot
−
1
1
Number of pods plant
(
−
1
)
=
−
grainyield in g
grain+strawyield in g
Grainharvest indexGHI
(
) =
grainweight pot in g
numberofgrains pot
−1
Hundred grainweight
()=
g
×
100
−1
pods pot
numberofgrains pot
−
1
Grainper pod
=
−
1
3.7.1.2 Experimental Results
The author conducted an experiment to study the influence of three sources of nitrogen and dif-
ferent N rates on the growth and yield of lowland rice (Table 3.15). The plant height, straw yield,
grain yield, and panicle density increased significantly with the addition of N fertilizer from the
three N sources (Table 3.15). The increase in plant height was quadratic with the addition of N
in the range of 0-400 mg kg
−1
from the three sources (Table 3.16). The variation in plant height
with the addition of N rate was 71% for ammonium sulfate, 84% for common urea, and 74% for
polymer-coated urea. Based on the regression equation, maximum plant height was achieved with
the addition of 407 mg N kg
−1
by ammonium sulfate, 674 mg N kg
−1
by common urea, and 232 mg
N kg
−1
by polymer-coated urea. Improvement in plant height with the addition of N has been
TABLE 3.15
Plant Height, Straw Yield, Grain Yield, and Panicle Density of Lowland Rice as Influenced
by N Rate and Sources
Treatments
a
Plant Height (cm)
Straw Yield (g Plant
−
1
)
Grain Yield (g Plant
−
1
)
Panicle Density (Plant
−
1
)
0 (control)
83.75d
5.91e
1.31ef
2.31bc
AS 100
95.50bcd
10.82d
5.25cd
4.56a
CU 100
93.75cd
11.08d
3.64de
3.31ab
PU 100
95.00bcd
13.25cd
3.12def
3.37ab
AS 200
101.75abc
14.08cd
7.84b
4.62a
CU 200
99.25abc
14.73c
7.00bc
4.37a
PU 200
100.25abc
15.52c
7.72b
4.43a
AS 400
108.50ab
20.86b
13.59a
5.12a
CU 400
110.50a
20.04b
7.29bc
3.43ab
PU 400
92.00cd
26.30a
0.77f
1.25c
Average
98.02
15.26
5.75
1.97
F-test
**
**
**
**
CV (%)
5.91
8.87
17.08
22.17
a
Treatments were: AS = ammonium sulfate, CU = common urea, PU = polymer-coated urea, and N rates were 0, 100, 200,
and 400 mg kg
−1
of soil.
**Significant at the 1% probability level. Means followed by the same letter in the same column are not significant at the 5%
probability level by Tukey's test.
