Abstract
Urea is the primary N source used for the large preflood N application in delayed‐flood rice ( Oryza sativa L.) production in the southern United States. Urea is prone to substantial NH 3 volatilization losses, however, if fields are not flooded quickly. Most delayed‐flood rice fields require 5 to 10 d to flood. Consequently, a study was conducted to evaluate the use of less NH 3 –volatile N sources for the preflood N application. The objectives were to evaluate the NH 3 volatilization loss and impact on N uptake and rice yield when urea, urea plus the urease inhibitor N ‐( n ‐butyl)thiophosphoric triamide (NBPT), (NH 4 ) 2 SO 4 , or a urea‐(NH 4 ) 2 SO 4 (UAS) blend were applied preflood and a flood established 1, 5, or 10 d after N application. When flooding was delayed for 5 or 10 d after N application, NH 3 volatilization was the least for urea + NBPT (2–10%) and (NH 4 ) 2 SO 4 (4–5%) and they produced the highest rice N uptake and yield. The UAS blend that had NH 3 volatilization losses (11–15%) at 5 and 10 d after application that were intermediate between urea (17–24%) and (NH 4 ) 2 SO 4 or urea + NBPT also had N uptake and grain yield intermediate between these N sources. Urea should only be used if ∼2 d are required to flood a field. If 3 to 5 d are required to flood a field, then UAS has some merits but it is not as consistent as (NH 4 ) 2 SO 4 or urea + NBPT. When >5 d are required to flood, (NH 4 ) 2 SO 4 or urea + NBPT should be used.
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Claims 9
Claim · model-written summary
With flooding delayed 5 or 10 days, urea plus NBPT had the least ammonia volatilization, 2–10%.
- Taxon
- rice
Oryza sativae1 - Treatment
- urea + NBPTe0
- Outcome
- NH 3 volatilizatione0
- Direction
- leaste0
- Value
- 2–10%e0
- Qualifier
- 5 or 10 de0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When flooding was delayed for 5 or 10 d after N application, NH 3 volatilization was the least for urea + NBPT (2–10%) and (NH 4 ) 2 SO 4 (4–5%)”
e1“rice ( Oryza sativa L.)”
Claim · model-written summary
With flooding delayed 5 or 10 days, ammonium sulfate had among the least ammonia volatilization, 4–5%.
- Taxon
- riceOryza sativae1
- Treatment
- (NH 4 ) 2 SO 4e0
- Outcome
- NH 3 volatilizatione0
- Direction
- leaste0
- Value
- 4–5%e0
- Qualifier
- 5 or 10 de0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When flooding was delayed for 5 or 10 d after N application, NH 3 volatilization was the least for urea + NBPT (2–10%) and (NH 4 ) 2 SO 4 (4–5%)”
e1“rice ( Oryza sativa L.)”
Claim · model-written summary
Urea plus NBPT produced the highest rice nitrogen uptake and yield after delayed flooding.
- Taxon
- riceOryza sativae0
- Treatment
- urea + NBPTe0
- Outcome
- rice N uptake and yielde0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“urea + NBPT (2–10%) and (NH 4 ) 2 SO 4 (4–5%) and they produced the highest rice N uptake and yield”
Claim · model-written summary
Ammonium sulfate produced the highest rice nitrogen uptake and yield after delayed flooding.
- Taxon
- riceOryza sativae0
- Treatment
- (NH 4 ) 2 SO 4e0
- Outcome
- rice N uptake and yielde0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“urea + NBPT (2–10%) and (NH 4 ) 2 SO 4 (4–5%) and they produced the highest rice N uptake and yield”
Claim · model-written summary
The UAS blend had intermediate ammonia volatilization losses of 11–15% at 5 and 10 days.
- Taxon
- riceOryza sativae1
- Treatment
- UAS blende0
- Outcome
- NH 3 volatilization lossese0
- Direction
- intermediatee0
- Value
- 11–15%e0
- Qualifier
- 17–24%e0
- Comparator
- ureae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The UAS blend that had NH 3 volatilization losses (11–15%) at 5 and 10 d after application that were intermediate between urea (17–24%) and (NH 4 ) 2 SO 4 or urea + NBPT”
e1“rice ( Oryza sativa L.)”
Claim · model-written summary
The UAS blend produced intermediate rice nitrogen uptake and grain yield.
- Taxon
- riceOryza sativae1
- Treatment
- UAS blende0
- Outcome
- N uptake and grain yielde0
- Direction
- intermediatee0
- Comparator
- ureae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The UAS blend that had NH 3 volatilization losses (11–15%) at 5 and 10 d after application that were intermediate between urea (17–24%) and (NH 4 ) 2 SO 4 or urea + NBPT also had N uptake and grain yield intermediate between these N sources”
e1“rice ( Oryza sativa L.)”
Claim · model-written summary
Use urea only when flooding takes about two days.
- Taxon
- riceOryza sativae1
- Outcome
- Urea should only be used if ∼2 d are required to flood a fielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Urea should only be used if ∼2 d are required to flood a field”
e1“rice ( Oryza sativa L.)”
Claim · model-written summary
UAS has some merit when flooding takes three to five days but is less consistent than ammonium sulfate or urea plus NBPT.
- Taxon
- riceOryza sativae1
- Outcome
- UAS has some merits but it is not as consistent as (NH 4 ) 2 SO 4 or urea + NBPTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“If 3 to 5 d are required to flood a field, then UAS has some merits but it is not as consistent as (NH 4 ) 2 SO 4 or urea + NBPT”
e1“rice ( Oryza sativa L.)”
Claim · model-written summary
Use ammonium sulfate or urea plus NBPT when flooding takes more than five days.
- Taxon
- riceOryza sativae1
- Outcome
- (NH 4 ) 2 SO 4 or urea + NBPT should be usede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When >5 d are required to flood, (NH 4 ) 2 SO 4 or urea + NBPT should be used”
e1“rice ( Oryza sativa L.)”
The same questions in other papers
nitrogen · yield · Oryza sativa (rice)Positive and negative results
1,802 papers in the same direction as this paper · 193 in the opposite direction · 49 reporting no difference from an alternative
- negative
- negative
- negative
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