Abstract
In the southern U.S. dry‐seeded, delayed‐flood rice ( Oryza sativa L.) culture system, there are two practices that can aggravate NH 3 volatilization losses of urea applied preflood: untimely application of the permanent flood and conservation tillage. The objectives of this study were to determine the influence of tillage practice, N source, and application time on NH 3 volatilization, N uptake, and grain yield of delayed flood rice grown on a clay and silt loam soil. Multisite field studies were conducted in 2000 and 2001 using both stale‐seedbed and conventional tillage practices with urea and (NH 4 ) 2 SO 4 applied 14 d preflood and urea 1 d preflood at four N rates. Ammonia volatilization was measured and plant samples were collected for N uptake and grain yield. Ammonia volatilization was the highest (14–32%) and N uptake and grain yield of rice the lowest when urea was applied 14 d preflood. Ammonium sulfate applied 14 d preflood lost little N (1.5–7%) via NH 3 volatilization and resulted in N uptake and grain yields of rice similar to urea applied 1 d preflood. The stale seedbed had no effect on NH 3 volatilization of (NH 4 ) 2 SO 4 and only affected urea in 1 yr on the silt loam soil when weedy residue was greater and the two tillage systems still produced rice with similar N uptakes and grain yields. Ammonia volatilization was more rapid and greater when urea was applied to the silt loam than to the clay. Ammonia volatilization loss of urea was impacted the most from delaying the flood and not from conservation tillage.
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Claims 13
Claim · model-written summary
Preflood urea applied 14 days early yielded highest Ammonia volatilization.
- Taxon
- rice
Oryza sativae0 - Treatment
- urea was applied 14 d prefloode0
- Outcome
- Ammonia volatilizatione0
- Direction
- higheste0
- Value
- 14–32%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonia volatilization was the highest (14–32%) and N uptake and grain yield of rice the lowest when urea was applied 14 d preflood.”
Claim · model-written summary
Preflood urea applied 14 days early yielded lowest N uptake.
- Taxon
- riceOryza sativae0
- Treatment
- urea was applied 14 d prefloode0
- Outcome
- N uptakee0
- Direction
- loweste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonia volatilization was the highest (14–32%) and N uptake and grain yield of rice the lowest when urea was applied 14 d preflood.”
Claim · model-written summary
Preflood urea applied 14 days early yielded lowest grain yield of rice.
- Taxon
- riceOryza sativae0
- Treatment
- urea was applied 14 d prefloode0
- Outcome
- grain yield of ricee0
- Direction
- loweste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonia volatilization was the highest (14–32%) and N uptake and grain yield of rice the lowest when urea was applied 14 d preflood.”
Claim · model-written summary
Ammonium sulfate applied 14 days preflood had low ammonia N loss of 1.5–7%.
- Taxon
- riceOryza sativae0
- Treatment
- Ammonium sulfate applied 14 d prefloode0
- Outcome
- lost little Ne0
- Direction
- littlee0
- Value
- 1.5–7%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonium sulfate applied 14 d preflood lost little N (1.5–7%) via NH 3 volatilization and resulted in N uptake and grain yields of rice similar to urea applied 1 d preflood.”
Claim · model-written summary
Ammonium sulfate 14 days preflood produced N uptake similar to urea one day preflood.
- Taxon
- riceOryza sativae0
- Treatment
- Ammonium sulfate applied 14 d prefloode0
- Outcome
- N uptakee0
- Direction
- similare0
- Comparator
- urea applied 1 d prefloode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonium sulfate applied 14 d preflood lost little N (1.5–7%) via NH 3 volatilization and resulted in N uptake and grain yields of rice similar to urea applied 1 d preflood.”
Claim · model-written summary
Ammonium sulfate 14 days preflood produced grain yields of rice similar to urea one day preflood.
- Taxon
- riceOryza sativae0
- Treatment
- Ammonium sulfate applied 14 d prefloode0
- Outcome
- grain yields of ricee0
- Direction
- similare0
- Comparator
- urea applied 1 d prefloode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonium sulfate applied 14 d preflood lost little N (1.5–7%) via NH 3 volatilization and resulted in N uptake and grain yields of rice similar to urea applied 1 d preflood.”
Claim · model-written summary
Stale seedbed had no effect on ammonium sulfate ammonia volatilization.
- Taxon
- riceOryza sativae0
- Treatment
- stale seedbede0
- Outcome
- NH 3 volatilization of (NH 4 ) 2 SO 4e0
- Direction
- no effecte0
- Comparator
- two tillage systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stale seedbed had no effect on NH 3 volatilization of (NH 4 ) 2 SO 4 and only affected urea in 1 yr on the silt loam soil when weedy residue was greater and the two tillage systems still produced rice with similar N uptakes and grain yields.”
Claim · model-written summary
Stale seedbed affected urea ammonia volatilization in one year on silt loam with more weedy residue.
- Taxon
- riceOryza sativae0
- Treatment
- stale seedbede0
- Outcome
- ureae0
- Qualifier
- in 1 yre0
- Comparator
- two tillage systemse0
- Setting
- silt loam soile0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stale seedbed had no effect on NH 3 volatilization of (NH 4 ) 2 SO 4 and only affected urea in 1 yr on the silt loam soil when weedy residue was greater and the two tillage systems still produced rice with similar N uptakes and grain yields.”
Claim · model-written summary
The two tillage systems gave similar rice N uptakes.
- Taxon
- riceOryza sativae0
- Treatment
- stale seedbede0
- Outcome
- N uptakese0
- Direction
- similare0
- Comparator
- two tillage systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stale seedbed had no effect on NH 3 volatilization of (NH 4 ) 2 SO 4 and only affected urea in 1 yr on the silt loam soil when weedy residue was greater and the two tillage systems still produced rice with similar N uptakes and grain yields.”
Claim · model-written summary
The two tillage systems gave similar rice grain yields.
- Taxon
- riceOryza sativae0
- Treatment
- stale seedbede0
- Outcome
- grain yieldse0
- Direction
- similare0
- Comparator
- two tillage systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stale seedbed had no effect on NH 3 volatilization of (NH 4 ) 2 SO 4 and only affected urea in 1 yr on the silt loam soil when weedy residue was greater and the two tillage systems still produced rice with similar N uptakes and grain yields.”
Claim · model-written summary
Urea on silt loam had more rapid ammonia volatilization than on clay.
- Taxon
- riceOryza sativat0
- Treatment
- urea was applied to the silt loame0
- Outcome
- Ammonia volatilizatione0
- Direction
- more rapide0
- Comparator
- the claye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonia volatilization was more rapid and greater when urea was applied to the silt loam than to the clay.”
t0“Ammonia Volatilization and Nitrogen Uptake for Conventional and Conservation Tilled Dry‐Seeded, Delayed‐Flood Rice”
Claim · model-written summary
Urea on silt loam had greater ammonia volatilization than on clay.
- Taxon
- riceOryza sativat0
- Treatment
- urea was applied to the silt loame0
- Outcome
- Ammonia volatilizatione0
- Direction
- greatere0
- Comparator
- the claye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonia volatilization was more rapid and greater when urea was applied to the silt loam than to the clay.”
t0“Ammonia Volatilization and Nitrogen Uptake for Conventional and Conservation Tilled Dry‐Seeded, Delayed‐Flood Rice”
Claim · model-written summary
Delaying the flood had the greater impact on urea ammonia volatilization loss than conservation tillage.
- Taxon
- RiceOryza sativat0
- Outcome
- Ammonia volatilization loss of ureae0
- Direction
- impacted the moste0
- Comparator
- conservation tillagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ammonia volatilization loss of urea was impacted the most from delaying the flood and not from conservation tillage.”
t0“Ammonia Volatilization and Nitrogen Uptake for Conventional and Conservation Tilled Dry‐Seeded, Delayed‐Flood Rice”
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