Yoshida - 1981 - Fundamentals of Rice Crop Science

142 FUNDAMENTALS OF RICE CROP SCIENCE
Table 3.19. Design of experiment for study of partial productive
efficiency.
Stage
I
II
III
IV
V
VI
VII
Vlll
IX
Period a
23 Jun– 6 Jul
6 Jul–15 Jul
15 Jul–23 Jul
23 Jul–31 Jul
31 Jul– 8 Aug
8 Aug–18 Aug
18 Aug–30 Aug
30 Aug–15 Sep
15 Sep–14 Oct
Days (cumulative no.)
after transplanting
14
23
31
39
47
57
69
85
114
a Transplanted on 23 June.
easily. In a classical work by Kimura and Chiba (1943), nitrogen was supplied in 9
different ways with respect to growth stages (Table 3.19, 3.20). To produce plants
that would contain different amounts of nitrogen, each supply had seven different
levels of nitrogen concentration in culture solution (Table 3.21). Thus, altogether
there were 63 treatments. The results of the above experiment are summarized in
Table 3.22 and Figure 3.13. From these results, several important conclusions can
be drawn:
• Nitrogen absorbed at early growth stages is used to produce more straw than
grain.
• Nitrogen absorbed at later growth stages is used to produce more grain than
straw.
• The partial productive efficiency for both grain and straw is higher when the
nitrogen supply is lower.
• There are two peaks in the partial productive efficiency for grain. The first is
not related to a particular growth stage but to the amount of nitrogen absorbed
Table 3.20. Supply and withdrawal of nitrogen for each stage. a
Treatment
Stage
I II Ill IV V VI VII Vlll IX
a
0 – – – – – – – –
b
0 0 – – – – – – –
c 0 0 0 – – – – – –
d 0 0 0 0 – – – – –
e
0 0 0 0 0 – – – –
f
0 0 0 0 0 0 – – –
g 0 0 0 0 0 0 0 – –
h 0 0 0 0 0 0 0 0 –
i 0 0 0 0 0 0 0 0 0
a 0 = supply, – = withdrawal.