Abstract
The limited understanding of soil nitrogen (N) effects on crop yield loss to weeds prevents the refinement of integrated weed management to consider soil fertility. A 3-yr field experiment compared ammonium nitrate applications before corn emergence (PRE N) or in late June (POST N) on the growth of giant foxtail, velvetleaf, common waterhemp, and grain corn. The N responses were studied in corn population densities of 5.4 and 7.9 plants m−2 to understand how crop density might influence N effects on yield loss. In late June of each year, leaf areas were 25% (corn), 64% (velvetleaf), and 41% (giant foxtail) lower with POST N than with PRE N. Common waterhemp leaf area in late June was unaffected by N timing. Corn population density did not affect weed shoot dry weights evaluated in late June. Corn and velvetleaf heights in late July were up to 19 and 48% lower, respectively, with POST N compared with PRE N. Common waterhemp and giant foxtail heights in late July were unaffected by N timing. Corn yield was decreased 13 to 18% by giant foxtail with POST N compared with PRE N. Velvetleaf seed yield was lower, but giant foxtail seed yield was higher, with POST N than with PRE N. Velvetleaf and giant foxtail seed yields were 23 to 56% and 30 to 62% lower, respectively, with the high corn population density compared with the low population density. In competition between corn and common waterhemp, neither N timing nor corn population affected corn yield loss or common waterhemp seed production. N management may alter weed competitiveness and weed seed production in corn, but fertilization recommendations may vary with the weed species that are present.
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Claims 17
Claim · model-written summary
POST N lowered corn leaf area by 25% relative to PRE N in late June.
- Taxon
- corn
Zea mays subsp. mayse0 - Treatment
- POST Ne0
- Outcome
- leaf arease0
- Direction
- lowere0
- Value
- 25%e0
- Comparator
- PRE Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf areas were 25% (corn), 64% (velvetleaf), and 41% (giant foxtail) lower with POST N than with PRE N”
Claim · model-written summary
POST N lowered velvetleaf leaf area by 64%.
- Taxon
- velvetleaf
Abutilon theophrastie0 - Treatment
- POST Ne0
- Outcome
- leaf arease0
- Direction
- lowere0
- Value
- 64%e0
- Comparator
- PRE Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf areas were 25% (corn), 64% (velvetleaf), and 41% (giant foxtail) lower with POST N than with PRE N”
Claim · model-written summary
POST N lowered giant foxtail leaf area by 41%.
Verbatim
e0“leaf areas were 25% (corn), 64% (velvetleaf), and 41% (giant foxtail) lower with POST N than with PRE N”
Claim · model-written summary
N timing did not affect common waterhemp leaf area.
Not reportedComparator
Verbatim
e0“Common waterhemp leaf area in late June was unaffected by N timing.”
Claim · model-written summary
Corn density did not affect weed shoot dry weight in late June.
- Taxon
- weede0
- Treatment
- Corn population densitye0
- Outcome
- weed shoot dry weightse0
- Direction
- did not affecte0
Not reportedComparator
Verbatim
e0“Corn population density did not affect weed shoot dry weights evaluated in late June.”
Claim · model-written summary
POST N lowered corn height by up to 19%.
- Taxon
- CornZea mays subsp. mayse0
- Treatment
- POST Ne0
- Outcome
- heightse0
- Direction
- lowere0
- Value
- 19e0
- Comparator
- PRE Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn and velvetleaf heights in late July were up to 19 and 48% lower, respectively, with POST N compared with PRE N.”
Claim · model-written summary
POST N lowered velvetleaf height by up to 48%.
- Taxon
- velvetleafAbutilon theophrastie0
- Treatment
- POST Ne0
- Outcome
- heightse0
- Direction
- lowere0
- Value
- 48%e0
- Comparator
- PRE Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn and velvetleaf heights in late July were up to 19 and 48% lower, respectively, with POST N compared with PRE N.”
Claim · model-written summary
N timing did not affect common waterhemp height.
Not reportedComparator
Verbatim
e0“Common waterhemp and giant foxtail heights in late July were unaffected by N timing.”
Claim · model-written summary
N timing did not affect giant foxtail height.
Not reportedComparator
Verbatim
e0“Common waterhemp and giant foxtail heights in late July were unaffected by N timing.”
Claim · model-written summary
Giant foxtail reduced corn yield by 13 to 18% with POST N relative to PRE N.
- Taxon
- CornZea mays subsp. mayse0
- Treatment
- giant foxtail with POST Ne0
- Interactor
- giant foxtaile0weed
- Outcome
- Corn yielde0
- Direction
- decreasede0
- Value
- 13 to 18%e0
- Comparator
- PRE Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn yield was decreased 13 to 18% by giant foxtail with POST N compared with PRE N.”
Claim · model-written summary
POST N lowered velvetleaf seed yield.
- Taxon
- VelvetleafAbutilon theophrastie0
- Treatment
- POST Ne0
- Outcome
- seed yielde0
- Direction
- lowere0
- Comparator
- PRE Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Velvetleaf seed yield was lower, but giant foxtail seed yield was higher, with POST N than with PRE N.”
Claim · model-written summary
POST N raised giant foxtail seed yield.
Verbatim
e0“Velvetleaf seed yield was lower, but giant foxtail seed yield was higher, with POST N than with PRE N.”
Claim · model-written summary
High corn density lowered velvetleaf seed yield by 23 to 56%.
- Taxon
- VelvetleafAbutilon theophrastie0
- Treatment
- high corn population densitye0
- Outcome
- seed yieldse0
- Direction
- lowere0
- Value
- 23 to 56%e0
- Comparator
- low population densitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Velvetleaf and giant foxtail seed yields were 23 to 56% and 30 to 62% lower, respectively, with the high corn population density compared with the low population density.”
Claim · model-written summary
High corn density lowered giant foxtail seed yield by 30 to 62%.
Verbatim
e0“Velvetleaf and giant foxtail seed yields were 23 to 56% and 30 to 62% lower, respectively, with the high corn population density compared with the low population density.”
Claim · model-written summary
Neither N timing nor corn density affected corn yield loss in competition with common waterhemp.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- N timing nor corn populatione0
- Interactor
- common waterhempe0weed
- Outcome
- corn yield losse0
- Direction
- neithere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In competition between corn and common waterhemp, neither N timing nor corn population affected corn yield loss or common waterhemp seed production.”
Claim · model-written summary
Neither N timing nor corn density affected common waterhemp seed production.
- Taxon
- common waterhempe0
- Treatment
- N timing nor corn populatione0
- Outcome
- common waterhemp seed productione0
- Direction
- neithere0
Not reportedComparator
Verbatim
e0“In competition between corn and common waterhemp, neither N timing nor corn population affected corn yield loss or common waterhemp seed production.”
Claim · model-written summary
Fertilization recommendations may depend on the weed species present.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- fertilization recommendationse0
- Qualifier
- weed species that are presente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fertilization recommendations may vary with the weed species that are present.”
t0“corn”
The same questions in other papers
Zea mays subsp. mays · yield · Zea mays (maize)Results differ
95 papers in the same direction as this paper · 196 in the opposite direction
- positive
- positive
- positive
288 papers more in this group
See all 292 papers →Zea mays subsp. mays · yield · Abutilon theophrasti (velvetleaf)Results agree
2 papers in the same direction as this paper
- positive
- positive
Alopecurus pratensis · yield · Zea mays (maize)Results agree
2 papers in the same direction as this paper
- negative
- negative
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.