Abstract
Abstract Short‐statured, high yielding rice ( Oryza sativa L.) varieties grown extensively in northern Peru require extremely high rates of conventional N sources to achieve maximum yields. The recovery of applied N is extremely low due to the use of intermittent flooding. This water management system results in heavy N losses even with properly timed split applications. In search of simpler and more efficient methods of N management, eight field experiments were conducted in the region to evaluate sulfur‐coated urea (SCU), an experimental, slow‐release N sources supplied by the Tennessee Valley Authority. Rice yields were increased an average of 59% more by pretransplant‐incorporated SCU than by urea or ammonium sulfate applied in the same manner. SCU produced an average of 20% higher grain yield response than topdressed applications of urea or ammonium sulfate. SCU applications increased panicle production, N uptake at harvest, and the apparent recovery of added N. Beneficial effects of SCU were more pronounced in sites where check yields were low, especially less than about 4.8 ton/ha. In sites with high N supplying capacity, SCU produced excessive vegetative growth which resulted in yield reductions at high N rates. Regardless of an assumed 48%‐higher unit N cost in SCU, the overall benefits of pretransplant‐incorporated applications of SCU were favorable since there was a decrease of 40% in the optimum rate of N and the need for precise timing of application was eliminated.
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Claims 10
Claim · model-written summary
Pretransplant incorporated SCU increased yield response 59% more than incorporated urea or ammonium sulfate.
- Taxon
- Rice
Oryza sativae0 - Treatment
- pretransplant‐incorporated SCUe0
- Outcome
- Rice yieldse0
- Direction
- increasede0
- Value
- 59%e0
- Comparator
- urea or ammonium sulfate applied in the same mannere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice yields were increased an average of 59% more by pretransplant‐incorporated SCU than by urea or ammonium sulfate applied in the same manner.”
Claim · model-written summary
SCU produced 20% higher grain yield response than topdressed urea or ammonium sulfate.
- Taxon
- riceOryza sativat0
- Treatment
- SCUe0
- Outcome
- grain yield responsee0
- Direction
- highere0
- Value
- 20%e0
- Comparator
- topdressed applications of urea or ammonium sulfatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SCU produced an average of 20% higher grain yield response than topdressed applications of urea or ammonium sulfate.”
t0“Rice”
Claim · model-written summary
SCU increased panicle production.
- Taxon
- riceOryza sativat0
- Treatment
- SCU applicationse0
- Outcome
- panicle productione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SCU applications increased panicle production, N uptake at harvest, and the apparent recovery of added N.”
t0“Rice”
Claim · model-written summary
SCU increased nitrogen uptake at harvest.
- Taxon
- riceOryza sativat0
- Treatment
- SCU applicationse0
- Outcome
- N uptake at harveste0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SCU applications increased panicle production, N uptake at harvest, and the apparent recovery of added N.”
t0“Rice”
Claim · model-written summary
SCU increased apparent recovery of added nitrogen.
- Taxon
- riceOryza sativat0
- Treatment
- SCU applicationse0
- Outcome
- apparent recovery of added Ne0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SCU applications increased panicle production, N uptake at harvest, and the apparent recovery of added N.”
t0“Rice”
Claim · model-written summary
SCU benefits were more pronounced where check yields were below about 4.8 ton/ha.
- Taxon
- riceOryza sativat0
- Outcome
- Beneficial effects of SCUe0
- Direction
- more pronouncede0
- Qualifier
- less than about 4.8 ton/hae0
- Setting
- sitese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Beneficial effects of SCU were more pronounced in sites where check yields were low, especially less than about 4.8 ton/ha.”
t0“Rice”
Claim · model-written summary
At high nitrogen rates in high nitrogen supplying sites, SCU produced excessive vegetative growth.
- Taxon
- riceOryza sativat0
- Treatment
- SCUe0
- Outcome
- excessive vegetative growthe0
- Direction
- excessivee0
- Setting
- sites with high N supplying capacitye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In sites with high N supplying capacity, SCU produced excessive vegetative growth which resulted in yield reductions at high N rates.”
t0“Rice”
Claim · model-written summary
At high nitrogen rates in high nitrogen supplying sites, SCU reduced yield.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In sites with high N supplying capacity, SCU produced excessive vegetative growth which resulted in yield reductions at high N rates.”
t0“Rice”
Claim · model-written summary
SCU lowered the optimum nitrogen rate by 40%.
- Taxon
- riceOryza sativat0
- Treatment
- pretransplant‐incorporated applications of SCUe0
- Outcome
- optimum rate of Ne0
- Direction
- decreasee0
- Value
- 40%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Regardless of an assumed 48%‐higher unit N cost in SCU, the overall benefits of pretransplant‐incorporated applications of SCU were favorable since there was a decrease of 40% in the optimum rate of N and the need for precise timing of application was eliminated.”
t0“Rice”
Claim · model-written summary
SCU removed the need for precise application timing.
- Taxon
- riceOryza sativat0
- Treatment
- pretransplant‐incorporated applications of SCUe0
- Outcome
- need for precise timing of applicatione0
- Direction
- eliminatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Regardless of an assumed 48%‐higher unit N cost in SCU, the overall benefits of pretransplant‐incorporated applications of SCU were favorable since there was a decrease of 40% in the optimum rate of N and the need for precise timing of application was eliminated.”
t0“Rice”
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