1National Institute of Crop Science, Suwon 441-857, Korea. www.nics.go.kr Email areum@rda.go.kr
2Department of Agronomy, Seoul National University, Suwon 441-744, Korea. www.snu.ac.kr Email hojinlee@snu.ac.kr
This study was conducted to investigate absorption and partition of nitrogen for improvement in efficiency of nitrogen. This experiment was carried out with two cultivars, Hwasungbyeo and Dasanbyeo (semi-dwarf) in paddy field. The levels of N treatments were 60, 120, 180 kg N per ha. Microplots (0.81m2) were established for 15N labeled fertilizer application. Nitrogen utilization differences between the two cultivars were associated with total nitrogen uptake and partitioning after heading. The ability to absorb soil nitrogen through the grain filling period contributed to the increased yield of Dasanbyeo.
This experiment was carried out with two rice cultivars, Hwasungbyeo and Dasanbyeo (semi-dwarf). Nitrogen utilization differences between two cultivars were associated with total nitrogen uptake and partitioning after heading. The ability to absorb soil nitrogen through the grain filling period contributed to the increased yield of Dasanbyeo.
Key Words
Rice, Hwasungbyeo, Dasanbyeo, 15N, Nitrogen, Uptake
In rice semi-dwarf cultivars bred for high grain yield have higher nitrogen use efficiencies than tall cultivars at high nitrogen application rate. Research on cultivars differing in plant type often shows differences in nitrogen uptake and use efficiency (Guindo et al., 1994). Accordingly, this study was conducted to investigate nitrogen absorption and partitioning by 15N labeled fertilizer between the different plant types of rice (Oryza sativa L.).
This experiment was carried out with two rice cultivars, Hwasungbyeo and Dasanbyeo in a paddy field. Hwasungbyeo (Suwon330) is a tall (culm length 82 cm), medium maturing variety, while Dasanbyeo (Suwon405) is a semi-dwarf (73 cm), medium maturing and high yielding variety. The N treatments were 60, 120, 180 kg N per ha. Microplots (0.81m2) were established for 15N labeled fertilizer (urea) application. Total nitrogen and 15N contents were determined by stable isotope mass spectrometer (Isoprime-EA, Micromass) at the National Instrumentation Center for Environmental Management (NICEM), Seoul National University, Korea.
At all N rates, Dasanbyeo exhibited an improved harvest index over Hwasungbyeo. Nitrogen uptake and accumulation in leaf blade and whole plant continued after heading in Dasanbyeo (Data not shown). Nitrogen utilization differences between the two cultivars were associated with nitrogen uptake and partitioning after heading. (Table 1). Yoshida (1981) reported that nitrogen absorption after heading would assume increased importance when high yields were achieved by increasing the harvest index. In Dasanbyeo, the ability to absorb soil nitrogen through the grain filling period contributed to high harvest index and yield.
Table 1. Nitrogen derived from fertilizer at heading and harvest in paddy field
N fertilizer rate |
Nitrogen derived from fertilizer (g/hill) | ||||||
Hwasungbyeo |
Dasanbyeo | ||||||
Heading |
Harvest |
Increment |
Heading |
Harvest |
Increment | ||
60 |
Basal |
0.03 |
0.05 |
0.03 |
0.05 |
||
TS |
0.02 |
0.02 |
0.02 |
0.02 |
|||
PIS |
0.03 |
0.04 |
0.02 |
0.04 |
|||
TNDFF |
0.08 |
0.11 |
0.03 |
0.07 |
0.11 |
0.04 | |
Soil |
0.36 |
0.57 |
0.21 |
0.33 |
0.54 |
0.21 | |
TN |
0.44 |
0.68 |
0.24 |
0.40 |
0.65 |
0.25 | |
120 |
Basal |
0.14 |
0.18 |
0.11 |
0.12 |
||
TS |
0.09 |
0.09 |
0.07 |
0.08 |
|||
PIS |
0.16 |
0.10 |
0.07 |
0.09 |
|||
TNDFF |
0.39 |
0.37 |
0.00 |
0.25 |
0.29 |
0.04 | |
Soil |
0.45 |
0.64 |
0.19 |
0.37 |
0.77 |
0.40 | |
TN |
0.84 |
1.01 |
0.17 |
0.62 |
1.06 |
0.44 | |
180 |
Basal |
0.10 |
0.23 |
0.23 |
0.21 |
||
TS |
0.11 |
0.11 |
0.09 |
0.14 |
|||
PIS |
0.09 |
0.15 |
0.18 |
0.15 |
|||
TNDFF |
0.30 |
0.49 |
0.19 |
0.50 |
0.50 |
0.00 | |
Soil |
0.67 |
0.87 |
0.20 |
0.27 |
0.82 |
0.55 | |
TN |
0.97 |
1.36 |
0.39 |
0.77 |
1.32 |
0.55 |
TS: Tillering stage PIS: Panicle initiation stage TNDFF: Total nitrogen derived from fertilizer TN: Total nitrogen
We could estimate that N uptake and translocation from root after heading contributed to high grain yield of Dasanbyeo. So it would be needed to study for improvement of root biomass and vigor after heading in high yielding variety like Dasanbyeo.
Guindo, D., B.R. Wells, and R.J. Norman. (1994). Cultivar and nitrogen rate influence on nitrogen uptake and partitioning in rice. Soil Sci. Soc. Am. J. 58, 840-845.
Roberts, S.R., J.E. Hill, D.M. Brandon, B.C. Miller, S.C. Scardaci, C.M. Wick, and J.F. Williams. (1993). Biological yield and harvest index in rice: nitrogen response of tall and semi-dwarf cultivars. J. Prod. Agric. 6, 585-588.
Yoshida, S. 1981. Fundamentals of rice crop science. Int. Rice Res. Inst., Los Banos, Philippines.