Abstract
Abstract Since the development of high yielding tropical rice ( Oryza sativa L.) cultivars like ‘IR8,’ attention has turned to the differences in grain quality among rice cultivars. In field experiments at the IRRI farm, we studied the optimum time for applying nitrogen to rice cultivars for maximum grain yield, highest milling yield, and maximum seed viability. We applied ammonium sulfate at 60 kg/ha N in the 1969 wet season and 150 kg/ha N in the 1970 dry season. We used the cultivars IR8, ‘IR20,’ ‘C4‐63,’ and ‘RD1’ in the 1969 wet season and IR8, IR20, ‘IR22,’ and RD1 in the 1970 dry season. Farmers in South and Southeast Asia grow these cultivars on millions of hectares. Split application of nitrogen increased grain yield over single basal application in some cultivars by minimizing lodging. Topdressing of nitrogen at heading increased the percentage of head rice (unbroken polished grains) which was associated with higher protein content under that treatment. IR22, whose percentage of head rice was higher than those of the other cultivars tested, showed no further increase in head rice with nitrogen topdressing. Based on maximum grain yield with highest milling recovery and seed viability, the best time for harvesting transplanted rice was between 30 and 42 days after heading in the wet season and between 28 and 34 days after heading in the dry season.
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Claims 8
Claim · model-written summary
Split nitrogen application increased grain yield over single basal application in some rice cultivars.
- Taxon
- rice
Oryza sativat0 - Treatment
- Split application of nitrogene0
- Outcome
- grain yielde0
- Direction
- increasede0
- Qualifier
- some cultivarse0
- Comparator
- single basal applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Split application of nitrogen increased grain yield over single basal application in some cultivars by minimizing lodging.”
t0“Rice”
Claim · model-written summary
Split nitrogen application minimized lodging in some rice cultivars.
- Taxon
- riceOryza sativat0
- Treatment
- Split application of nitrogene0
- Outcome
- lodginge0
- Direction
- minimizinge0
- Qualifier
- some cultivarse0
- Comparator
- single basal applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Split application of nitrogen increased grain yield over single basal application in some cultivars by minimizing lodging.”
t0“Rice”
Claim · model-written summary
Nitrogen topdressing at heading increased head rice percentage.
- Taxon
- riceOryza sativat0
- Treatment
- Topdressing of nitrogen at headinge0
- Outcome
- percentage of head ricee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Topdressing of nitrogen at heading increased the percentage of head rice (unbroken polished grains) which was associated with higher protein content under that treatment.”
t0“Rice”
Claim · model-written summary
Head rice percentage was associated with higher protein content under heading-stage nitrogen topdressing.
- Taxon
- riceOryza sativat0
- Treatment
- that treatmente0
- Outcome
- percentage of head ricee0
- Qualifier
- higher protein contente0
Not reportedCompoundDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the percentage of head rice (unbroken polished grains) which was associated with higher protein content under that treatment.”
t0“Rice”
Claim · model-written summary
IR22 had a higher head rice percentage than the other tested cultivars.
- Taxon
- riceOryza sativat0
- Material
- IR22e0
- Outcome
- percentage of head ricee0
- Direction
- highere0
- Comparator
- other cultivars testede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IR22, whose percentage of head rice was higher than those of the other cultivars tested”
t0“Rice”
Claim · model-written summary
IR22 showed no further increase in head rice from nitrogen topdressing.
- Taxon
- riceOryza sativat0
- Material
- IR22e0
- Treatment
- nitrogen topdressinge0
- Outcome
- head ricee0
- Direction
- no further increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IR22, whose percentage of head rice was higher than those of the other cultivars tested, showed no further increase in head rice with nitrogen topdressing.”
t0“Rice”
Claim · model-written summary
The recommended wet-season rice harvest window was 30 to 42 days after heading for maximum yield, milling recovery and seed viability.
- Taxon
- riceOryza sativae0
- Outcome
- best time for harvesting transplanted ricee0
- Value
- 30 and 42 days after headinge0
- Qualifier
- wet seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Based on maximum grain yield with highest milling recovery and seed viability, the best time for harvesting transplanted rice was between 30 and 42 days after heading in the wet season and between 28 and 34 days after heading in the dry season.”
Claim · model-written summary
The recommended dry-season rice harvest window was 28 to 34 days after heading for maximum yield, milling recovery and seed viability.
- Taxon
- riceOryza sativae0
- Outcome
- best time for harvesting transplanted ricee0
- Value
- 28 and 34 days after headinge0
- Qualifier
- dry seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Based on maximum grain yield with highest milling recovery and seed viability, the best time for harvesting transplanted rice was between 30 and 42 days after heading in the wet season and between 28 and 34 days after heading in the dry season.”
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