Abstract
Urease inhibitors are applied to reduce NH 3 volatilization and immobilization losses from surface‐applied urea or urea‐NH 4 NO 3 solutions (UAN). The urease inhibitor N‐(n‐butyl) thiophosphoric triamide (NBPT) was evaluated in the USA in 78 trials conducted with corn ( Zea mays L.) from 1984 to 1989. NBPT was applied with urea at rates of 0.25 to 1.0% (w/w) and with UAN at rates of 0.5 to 2.0 lb/acre. When averaged over N and NBPT rates for all locations and years of the study, NBPT increased grain yields by 4.3 bu/acre when applied with urea and by 1.6 bu/acre when applied with UAN. Average responses to NBPT were higher on sites that were able to respond to N conserved by NBPT (5.0 bu/acre for urea and 2.8 bu/acre for UAN). Average responses to NBPT were also greater on sites where nonvolatile N (NVN) treatments gave higher yields than unamended urea (6.6 bu/acre for urea and 2.7 bu/acre for UAN). Results from 21 trials employing multiple N rates showed that maximum grain yields could be obtained using an average of 74 lb/acre less N when NBPT was included with surface‐applied urea. These results demonstrate that NBPT provides an effective alternative to excessive rates of surface‐applied urea that are currently used to ensure that N will not limit grain yields.
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Claims 7
Claim · model-written summary
NBPT with urea increased corn grain yield by 4.3 bu/acre overall.
- Taxon
- Corn
Zea mays subsp. mayst0 - Treatment
- NBPTe0
- Outcome
- grain yieldse0
- Direction
- increasede0
- Value
- 4.3 bu/acree0
- Qualifier
- ureae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NBPT increased grain yields by 4.3 bu/acre when applied with urea”
t0“Corn Yield”
Claim · model-written summary
NBPT with UAN increased corn grain yield by 1.6 bu/acre overall.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- UANe0
- Outcome
- Yieldt0
- Direction
- increaseinferrede0
- Value
- 1.6 bu/acree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“by 1.6 bu/acre when applied with UAN”
t0“Corn Yield”
Claim · model-written summary
On nitrogen-responsive sites, NBPT with urea increased yield by 5.0 bu/acre.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- NBPTe0
- Outcome
- Yieldt0
- Direction
- highere0
- Value
- 5.0 bu/acree0
- Setting
- sites that were able to respond to N conserved by NBPTe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“responses to NBPT were higher on sites that were able to respond to N conserved by NBPT (5.0 bu/acre for urea”
t0“Corn Yield”
Claim · model-written summary
On nitrogen-responsive sites, NBPT with UAN increased yield by 2.8 bu/acre.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- UANe0
- Outcome
- Yieldt0
- Direction
- increaseinferrede0
- Value
- 2.8 bu/acree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2.8 bu/acre for UAN”
t0“Corn Yield”
Claim · model-written summary
Where NVN outyielded unamended urea, NBPT with urea increased yield by 6.6 bu/acre.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- NBPTe0
- Outcome
- yieldse0
- Direction
- greatere0
- Value
- 6.6 bu/acree0
- Comparator
- unamended ureae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“responses to NBPT were also greater on sites where nonvolatile N (NVN) treatments gave higher yields than unamended urea (6.6 bu/acre for urea”
t0“Corn Yield”
Claim · model-written summary
Where NVN outyielded unamended urea, NBPT with UAN increased yield by 2.7 bu/acre.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- UANe0
- Outcome
- Yieldt0
- Direction
- increaseinferrede0
- Value
- 2.7 bu/acree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2.7 bu/acre for UAN”
t0“Corn Yield”
Claim · model-written summary
NBPT with surface-applied urea allowed maximum grain yield with 74 lb/acre less nitrogen.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maximum grain yields could be obtained using an average of 74 lb/acre less N when NBPT was included with surface‐applied urea”
t0“Corn Yield”
The same questions in other papers
nitrogen · yield · Zea mays (maize)Positive and negative results
1,905 papers in the same direction as this paper · 234 in the opposite direction · 45 reporting no difference from an alternative
- no effect
- negative
- negative
2,181 papers more in this group
See all 2,185 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.