Abstract
We compared the seedbanks, seed rains, plant densities and biomasses of weeds under two contrasting systems of management in beet, maize and spring oilseed rape. Weed seedbank and plant density were measured at the same locations in two subsequent seasons. About 60 fields were sown with each crop. Each field was split, one half being sown with a conventional variety managed according to the farmer's normal practice, the other half being sown with a genetically modified herbicide-tolerant (GMHT) variety, with weeds controlled by a broad-spectrum herbicide. In beet and rape, plant densities shortly after sowing were higher in the GMHT treatment. Following weed control in conventional beet, plant densities were approximately one-fifth of those in GMHT beet. In both beet and rape, this effect was reversed after the first application of broad-spectrum herbicide, so that late-season plant densities were lower in the GMHT treatments. Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments. The effects of differing weed-seed returns in these two crops persisted in the seedbank: densities following the GMHT treatment were about 20% lower than those following the conventional treatment. The effect of growing maize was quite different. Weed density was higher throughout the season in the GMHT treatment. Late-season biomass was 82% higher and seed rain was 87% higher than in the conventional treatment. The difference was not subsequently detectable in the seedbank because the total seed return was low after both treatments. In all three crops, weed diversity was little affected by the treatment, except for transient effects immediately following herbicide application.
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Claims 16
Claim · model-written summary
Early plant density was higher in GMHT beet.
- Taxon
- beet
Beta vulgarise0 - Treatment
- GMHT treatmente0
- Interactor
- weedse1weed
- Outcome
- plant densitiese0
- Direction
- highere0
- Comparator
- conventional varietye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In beet and rape, plant densities shortly after sowing were higher in the GMHT treatment.”
e1“weeds under two contrasting systems of management”
e2“conventional variety managed according to the farmer's normal practice”
Claim · model-written summary
Early plant density was higher in GMHT rape.
- Taxon
- rape
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napuse0 - Treatment
- GMHT treatmente0
- Interactor
- weedse1weed
- Outcome
- plant densitiese0
- Direction
- highere0
- Comparator
- conventional varietye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“In beet and rape, plant densities shortly after sowing were higher in the GMHT treatment.”
e1“weeds under two contrasting systems of management”
e2“conventional variety managed according to the farmer's normal practice”
Claim · model-written summary
After conventional beet weed control, weed density was about one-fifth of GMHT beet.
- Taxon
- beetBeta vulgarise0
- Treatment
- weed control in conventional beete0
- Interactor
- weedse1weed
- Outcome
- plant densitiese0
- Value
- one-fifthe0
- Comparator
- GMHT beete0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Following weed control in conventional beet, plant densities were approximately one-fifth of those in GMHT beet.”
e1“weeds under two contrasting systems of management”
Claim · model-written summary
Late-season weed density became lower in GMHT beet after herbicide application.
- Taxon
- beetBeta vulgarise0
- Treatment
- GMHT treatmentse0
- Interactor
- weedse1weed
- Outcome
- late-season plant densitiese0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both beet and rape, this effect was reversed after the first application of broad-spectrum herbicide, so that late-season plant densities were lower in the GMHT treatments.”
e1“weeds under two contrasting systems of management”
Claim · model-written summary
Late-season weed density became lower in GMHT rape after herbicide application.
- Taxon
- rapeBrassica napuse0
- Treatment
- GMHT treatmentse0
- Interactor
- weedse1weed
- Outcome
- late-season plant densitiese0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both beet and rape, this effect was reversed after the first application of broad-spectrum herbicide, so that late-season plant densities were lower in the GMHT treatments.”
e1“weeds under two contrasting systems of management”
Claim · model-written summary
GMHT beet weed biomass was one-third to one-sixth of conventional treatment.
- Taxon
- beetBeta vulgarise1
- Treatment
- GMHT cropse0
- Interactor
- weedse2weed
- Outcome
- Biomasse0
- Value
- between one-third and one-sixthe0
- Comparator
- conventional treatmentse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments.”
e1“In beet and rape”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
GMHT rape weed biomass was one-third to one-sixth of conventional treatment.
- Taxon
- rapeBrassica napuse1
- Treatment
- GMHT cropse0
- Interactor
- weedse2weed
- Outcome
- Biomasse0
- Value
- between one-third and one-sixthe0
- Comparator
- conventional treatmentse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments.”
e1“In beet and rape”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
GMHT beet weed seed rain was one-third to one-sixth of conventional treatment.
- Taxon
- beetBeta vulgarise1
- Treatment
- GMHT cropse0
- Interactor
- weedse2weed
- Outcome
- seed raine0
- Value
- between one-third and one-sixthe0
- Comparator
- conventional treatmentse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments.”
e1“In beet and rape”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
GMHT rape weed seed rain was one-third to one-sixth of conventional treatment.
- Taxon
- rapeBrassica napuse1
- Treatment
- GMHT cropse0
- Interactor
- weedse2weed
- Outcome
- seed raine0
- Value
- between one-third and one-sixthe0
- Comparator
- conventional treatmentse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biomass and seed rain in GMHT crops were between one-third and one-sixth of those in conventional treatments.”
e1“In beet and rape”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
Subsequent weed seedbank density was about 20% lower after GMHT beet.
- Taxon
- beetBeta vulgarise1
- Treatment
- GMHT treatmente0
- Interactor
- weedse2weed
- Outcome
- densitiese0
- Direction
- lowere0
- Value
- 20%e0
- Comparator
- conventional treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“densities following the GMHT treatment were about 20% lower than those following the conventional treatment.”
e1“In beet and rape”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
Subsequent weed seedbank density was about 20% lower after GMHT rape.
- Taxon
- rapeBrassica napuse1
- Treatment
- GMHT treatmente0
- Interactor
- weedse2weed
- Outcome
- densitiese0
- Direction
- lowere0
- Value
- 20%e0
- Comparator
- conventional treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“densities following the GMHT treatment were about 20% lower than those following the conventional treatment.”
e1“In beet and rape”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
Weed density remained higher through the season under GMHT maize.
- Treatment
- GMHT treatmente0
- Interactor
- Weede0weed
- Outcome
- Weed densitye0
- Direction
- highere0
- Comparator
- conventional varietye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effect of growing maize was quite different. Weed density was higher throughout the season in the GMHT treatment.”
e1“conventional variety managed according to the farmer's normal practice”
Claim · model-written summary
Late-season weed biomass in GMHT maize was 82% higher.
- Treatment
- GMHTe3
- Interactor
- weedse2weed
- Outcome
- Late-season biomasse0
- Direction
- highere0
- Value
- 82%e0
- Comparator
- conventional treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Late-season biomass was 82% higher and seed rain was 87% higher than in the conventional treatment.”
e1“The effect of growing maize was quite different.”
e2“weeds under two contrasting systems of management”
e3“Weed density was higher throughout the season in the GMHT treatment.”
Claim · model-written summary
Weed seed rain in GMHT maize was 87% higher.
- Treatment
- GMHT treatmente2
- Interactor
- weedse3weed
- Outcome
- seed raine0
- Direction
- highere0
- Value
- 87%e0
- Comparator
- conventional treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Late-season biomass was 82% higher and seed rain was 87% higher than in the conventional treatment.”
e1“The effect of growing maize was quite different.”
e2“Weed density was higher throughout the season in the GMHT treatment.”
e3“weeds under two contrasting systems of management”
Claim · model-written summary
The maize seedbank difference was not detectable because seed return was low in both treatments.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The difference was not subsequently detectable in the seedbank because the total seed return was low after both treatments.”
e1“growing maize”
e2“weeds under two contrasting systems of management”
Claim · model-written summary
Weed diversity was little affected by treatment in all three crops except immediately after herbicide use.
- Taxon
- beet, maize and spring oilseed rapeBrassica napus
Zea maysBeta vulgarise1 - Treatment
- herbicide applicatione0
- Interactor
- weede0weed
- Outcome
- weed diversitye0
- Direction
- little affectede0
- Qualifier
- except for transient effects immediately following herbicide applicatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In all three crops, weed diversity was little affected by the treatment, except for transient effects immediately following herbicide application.”
e1“beet, maize and spring oilseed rape”
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See all 63 papers →8 of 11 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.