Abstract
A field study was conducted from 1987 to 1992 to determine the effectiveness of several treatments consisting of combinations of glyphosate and/or quizalofop with tillage to control quackgrass in legume plowdown and continuous annual crop rotations. The treatments were imposed on the quackgrass in 1987 and/or 1988, evaluated in 1989 (cycle 1), reimposed on the same plots in 1990 and/or 1991 and re-evaluated in 1992 (cycle 2). Where continuous barley was grown, glyphosate applied at 0.45 kg/ha before seeding in 1987 (cycle 1) and 1990 (cycle 2), and combined with fall tillage in the first two years of each cycle, reduced quackgrass shoot density and rhizome dry weight by more than 96%. In a legume plowdown rotation, consisting of barley underseeded to red clover followed by plowdown and barley in subsequent years, quackgrass was reduced by a similar amount by glyphosate at 0.45 kg/ha applied in 1987 and 1990 before seeding or in 1988 and 1991 at 5 d before or 6 wk after red clover plowdown. Quackgrass reduction from all of these treatments was as effective as the labelled rate of glyphosate (0.90 kg/ha) applied at the same times, and also as effective as glyphosate applied at 0.45 kg/ha in combination with tillage in a year of fallow. Without fall tillage the efficacy of glyphosate applied before seeding was reduced. Quizalofop at 0.20 kg/ha applied to canola in a rotation of canola followed by two years of barley, reduced quackgrass, but was less effective than glyphosate treatments with fall tillage. Reducing quackgrass populations resulted in significant increases in crop yields.
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Claims 7
Claim · model-written summary
Glyphosate with fall tillage reduced quackgrass shoot density by more than 96% in continuous barley.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree0 - Treatment
- glyphosate applied at 0.45 kg/ha before seedinge0
- Interactor
- quackgrasse0weed
- Outcome
- quackgrass shoot densitye0
- Direction
- reducede0
- Value
- more than 96%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Where continuous barley was grown, glyphosate applied at 0.45 kg/ha before seeding in 1987 (cycle 1) and 1990 (cycle 2), and combined with fall tillage in the first two years of each cycle, reduced quackgrass shoot density and rhizome dry weight by more than 96%”
Claim · model-written summary
Glyphosate with fall tillage reduced quackgrass rhizome dry weight by more than 96% in continuous barley.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- glyphosate applied at 0.45 kg/ha before seedinge0
- Interactor
- quackgrasse0weed
- Outcome
- rhizome dry weighte0
- Direction
- reducede0
- Value
- more than 96%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Where continuous barley was grown, glyphosate applied at 0.45 kg/ha before seeding in 1987 (cycle 1) and 1990 (cycle 2), and combined with fall tillage in the first two years of each cycle, reduced quackgrass shoot density and rhizome dry weight by more than 96%”
Claim · model-written summary
Glyphosate in a legume plowdown rotation reduced quackgrass by a similar amount.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- glyphosate at 0.45 kg/hae0
- Interactor
- quackgrasse0weed
- Outcome
- quackgrasse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“quackgrass was reduced by a similar amount by glyphosate at 0.45 kg/ha applied in 1987 and 1990 before seeding or in 1988 and 1991 at 5 d before or 6 wk after red clover plowdown”
e1“consisting of barley underseeded to red clover”
Claim · model-written summary
The reduced glyphosate treatments controlled quackgrass as effectively as the labelled rate.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- all of these treatmentse0
- Interactor
- Quackgrasse0weed
- Outcome
- Quackgrass reductione0
- Direction
- as effectivee0
- Comparator
- labelled rate of glyphosate (0.90 kg/ha)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Quackgrass reduction from all of these treatments was as effective as the labelled rate of glyphosate (0.90 kg/ha) applied at the same times”
e1“barley underseeded to red clover”
Claim · model-written summary
Omitting fall tillage reduced pre-seeding glyphosate efficacy.
- Taxon
- barleyHordeum vulgaree1
- Treatment
- Without fall tillagee0
- Outcome
- efficacy of glyphosatee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Without fall tillage the efficacy of glyphosate applied before seeding was reduced”
e1“Where continuous barley was grown”
Claim · model-written summary
Quizalofop reduced quackgrass in a canola rotation, but was less effective than glyphosate with fall tillage.
- Taxon
- canola
.jpg?width=60)
Brassica napus var. napuse0 - Treatment
- Quizalofop at 0.20 kg/hae0
- Interactor
- quackgrasse0weed
- Outcome
- quackgrasse0
- Direction
- reducede0
- Comparator
- glyphosate treatments with fall tillagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Quizalofop at 0.20 kg/ha applied to canola in a rotation of canola followed by two years of barley, reduced quackgrass, but was less effective than glyphosate treatments with fall tillage”
Claim · model-written summary
Reduced quackgrass populations significantly increased crop yields.
Verbatim
e0“Reducing quackgrass populations resulted in significant increases in crop yields”
t0“Annual Crop”
The same questions in other papers
glyphosate · growth · Hordeum vulgare (barley)Results differ
1 paper in the same direction as this paper · 4 in the opposite direction
- negative
- no effect
- negative
2 papers more in this group
See all 6 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.