Abstract
Glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Wats) is redefining row crop weed management in the southeast United States due to its widespread distribution, high competitive ability, copious seed production, and resilience against standard weed management programs. Herbicides alone are failing to provide adequate control of GR Palmer amaranth; thus, use of conventional tillage is increasing in the Southeast in order to control GR Palmer amaranth. Cultural practices consistent with maintenance of conservation tillage were evaluated to determine if they could suppress weeds in cotton (Gossypium hirsutum L.). An on-farm research and demonstration project was initiated in the fall of 2009 in Alabama, Georgia, South Carolina, and Tennessee to address well-founded concerns that conservation tillage systems were at risk because of GR Palmer amaranth. The research continued in certain states for two additional years. Cultural practices contrasted in the conservation tillage system were a no-till planted high-residue cover crop, one-time fall inversion tillage followed by the planting of a high-residue cover crop, and winter fallow only without a cover crop. Cover crop biomass yields varied from 570 to 6,790 kg ha−1 (509 to 6,063 lb ac−1) depending on location, type of cover crop, planting date, and environment. Fall inversion tillage increased cover crop biomass at all locations, likely due to preparation of a favorable seed bed for seedling establishment or alleviation of soil compaction or both. One-time fall inversion tillage reduced the number of GR Palmer amaranth escapes compared with the other treatments. Where GR Palmer amaranth densities were relatively low (approximately 1,000 plants ha−1 [405 plants ac−1] or fewer), there were few differences in the number of GR Palmer amaranth escapes among treatments. Where GR Palmer amaranth densities were relatively high (18,000 plants ha−1 [7,284 plants ac−1] or greater), winter fallow systems had higher Palmer amaranth densities escaping weed management programs compared to either cover crop system. The number of Palmer amaranth escapes declined exponentially as a function of cover crop biomass regardless of tillage. For sites with two years of data, no year by treatment interaction was detected, indicating that relative GR Palmer amaranth escape densities were sustained in each treatment for two seasons. Trends in cotton yields were the opposite of those for Palmer amaranth escapes. High-residue cover crops tended to suppress Palmer amaranth and increase cotton lint yields. However, no cultural management system consistently netted greater returns than other systems across locations and years.
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Claims 11
Claim · model-written summary
Cover crop biomass varied by location, crop, planting date and environment.
- Taxon
- cotton
Gossypium hirsutumt0 - Outcome
- Cover crop biomass yieldse0
- Value
- 570 to 6,790 kg ha−1e0
- Setting
- locatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cover crop biomass yields varied from 570 to 6,790 kg ha−1 (509 to 6,063 lb ac−1) depending on location, type of cover crop, planting date, and environment.”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
Fall inversion tillage increased cover crop biomass at all locations.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- Fall inversion tillagee0
- Outcome
- cover crop biomasse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fall inversion tillage increased cover crop biomass at all locations”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
Fall inversion tillage reduced Palmer amaranth escapes relative to other treatments.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- One-time fall inversion tillagee0
- Interactor
- GR Palmer amaranthe0weed
- Outcome
- number of GR Palmer amaranth escapese0
- Direction
- reducede0
- Comparator
- the other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“One-time fall inversion tillage reduced the number of GR Palmer amaranth escapes compared with the other treatments.”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
At low Palmer amaranth density, treatment differences in escapes were few.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- treatmentse0
- Interactor
- GR Palmer amaranthe0weed
- Outcome
- number of GR Palmer amaranth escapese0
- Direction
- few differencese0
- Qualifier
- approximately 1,000 plants ha−1 [405 plants ac−1] or fewere0
- Comparator
- among treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Where GR Palmer amaranth densities were relatively low (approximately 1,000 plants ha−1 [405 plants ac−1] or fewer), there were few differences in the number of GR Palmer amaranth escapes among treatments.”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
At high Palmer amaranth density, winter fallow had more weed escapes than either cover crop system.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- winter fallow systemse0
- Interactor
- Palmer amaranthe0weed
- Outcome
- Palmer amaranth densities escaping weed management programse0
- Direction
- highere0
- Qualifier
- 18,000 plants ha−1 [7,284 plants ac−1] or greatere0
- Comparator
- either cover crop systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Where GR Palmer amaranth densities were relatively high (18,000 plants ha−1 [7,284 plants ac−1] or greater), winter fallow systems had higher Palmer amaranth densities escaping weed management programs compared to either cover crop system.”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
Palmer amaranth escapes fell exponentially as cover crop biomass rose, regardless of tillage.
- Taxon
- cottonGossypium hirsutumt0
- Interactor
- Palmer amaranthe0weed
- Outcome
- number of Palmer amaranth escapese0
- Direction
- declined exponentiallye0
- Qualifier
- regardless of tillagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number of Palmer amaranth escapes declined exponentially as a function of cover crop biomass regardless of tillage.”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
No year by treatment interaction was detected at sites with two years of data.
- Taxon
- cottonGossypium hirsutumt0
- Outcome
- year by treatment interactione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For sites with two years of data, no year by treatment interaction was detected”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
Cotton yield trends opposed Palmer amaranth escape trends.
- Taxon
- cottonGossypium hirsutume0
- Interactor
- Palmer amaranthe0weed
- Outcome
- cotton yieldse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Trends in cotton yields were the opposite of those for Palmer amaranth escapes.”
Claim · model-written summary
High-residue cover crops tended to suppress Palmer amaranth.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- High-residue cover cropse0
- Interactor
- Palmer amaranthe0weed
- Outcome
- Palmer amaranthe0
- Direction
- suppresse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High-residue cover crops tended to suppress Palmer amaranth”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
Claim · model-written summary
High-residue cover crops tended to increase cotton lint yields.
- Taxon
- cottonGossypium hirsutume0
- Treatment
- High-residue cover cropse0
- Outcome
- cotton lint yieldse0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High-residue cover crops tended to suppress Palmer amaranth and increase cotton lint yields.”
Claim · model-written summary
No cultural management system consistently produced greater returns across locations and years.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- cultural management systeme0
- Outcome
- returnse0
- Direction
- greatere0
- Qualifier
- across locations and yearse0
- Comparator
- other systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no cultural management system consistently netted greater returns than other systems across locations and years.”
t0“High-residue cover crops alone or with strategic tillage to manage glyphosate-resistant Palmer amaranth ( Amaranthus palmeri ) in southeastern cotton ( Gossypium hirsutum )”
The same questions in other papers
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- negative
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5 papers in the same direction as this paper · 2 in the opposite direction · 1 reporting no difference from an alternative
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4 papers in the same direction as this paper · 25 reporting no difference from an alternative
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29 papers in the same direction as this paper · 5 in the opposite direction · 1 reporting no difference from an alternative
- positive
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See all 36 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.