Abstract
With the number of glyphosate-resistant weed species increasing in North America and a lack of new herbicide chemistries being developed, growers are shifting toward using older herbicides that are more expensive and may be less environmentally friendly. Therefore, to determine which weed management strategies are most cost effective and have the lowest impact on the environment we evaluated the efficacy, environmental impact, and the profitability of several weed management strategies in glyphosate-resistant soybean over a 3-yr period (2007 to 2009) at three locations in southwestern Ontario, Canada. No visible injury to soybean was observed with the herbicide treatments evaluated. A sequential application of glyphosate consistently provided high levels of weed control (99 to 100%) at 56 d after treatment in comparison with one- or two-pass herbicide programs. Soybean yield did not differ between the two-pass herbicide programs and glyphosate applied early POST; however, a yield benefit was found with a sequential application of glyphosate or a PRE herbicide followed by glyphosate compared with glyphosate applied only at late POST. The two-pass herbicide programs had higher environmental impact (EI) (> 23) than the one-pass herbicide programs (< 15), except when imazethapyr was followed by or tank-mixed with glyphosate, which had an equivalent EI (∼ 14) to the one-pass herbicide programs. Not surprisingly because of the low purchase price of glyphosate, gross margins were highest for treatments that included glyphosate. However, to reduce the selection pressure on glyphosate-resistant weed biotypes, to reduce environmental impact, and to increase gross margins a combination of glyphosate with another mode of action would be most beneficial. In this study glyphosate + imazethapyr was the best alternative to a sequential two-pass glyphosate program.
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Claims 10
Claim · model-written summary
No visible injury to soybean was observed with the herbicide treatments evaluated.
- Taxon
- soybean
Glycine maxt0 - Treatment
- herbicide treatmentse1
- Outcome
- visible injury to soybeane1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e1“No visible injury to soybean was observed with the herbicide treatments evaluated”
Claim · model-written summary
Sequential glyphosate application gave consistently high weed control (99 to 100%) at 56 days after treatment compared with one- or two-pass programs.
- Taxon
- soybeanGlycine maxt0
- Treatment
- sequential application of glyphosatee2
- Outcome
- weed controle2
- Direction
- provided high levelse2
- Value
- 99 to 100%e2
- Qualifier
- at 56 d after treatmente2
- Comparator
- one- or two-pass herbicide programse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e2“A sequential application of glyphosate consistently provided high levels of weed control (99 to 100%) at 56 d after treatment in comparison with one- or two-pass herbicide programs”
Claim · model-written summary
Soybean yield did not differ between two-pass herbicide programs and glyphosate applied early POST.
- Taxon
- soybeanGlycine maxt0
- Treatment
- two-pass herbicide programse3
- Outcome
- Soybean yielde3
- Direction
- did not differe3
- Comparator
- glyphosate applied early POSTe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e3“Soybean yield did not differ between the two-pass herbicide programs and glyphosate applied early POST”
Claim · model-written summary
Sequential application of glyphosate gave a yield benefit compared with glyphosate applied only at late POST.
- Taxon
- soybeanGlycine maxt0
- Treatment
- sequential application of glyphosatee4
- Outcome
- yielde4
- Direction
- yield benefite4
- Comparator
- glyphosate applied only at late POSTe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e4“a yield benefit was found with a sequential application of glyphosate or a PRE herbicide followed by glyphosate compared with glyphosate applied only at late POST”
Claim · model-written summary
A PRE herbicide followed by glyphosate gave a yield benefit compared with glyphosate applied only at late POST.
- Taxon
- soybeanGlycine maxt0
- Treatment
- a PRE herbicide followed by glyphosatee4
- Outcome
- yielde4
- Direction
- yield benefite4
- Comparator
- glyphosate applied only at late POSTe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e4“a yield benefit was found with a sequential application of glyphosate or a PRE herbicide followed by glyphosate compared with glyphosate applied only at late POST”
Claim · model-written summary
Two-pass herbicide programs had higher environmental impact than one-pass programs.
- Taxon
- soybeanGlycine maxt0
- Treatment
- two-pass herbicide programse5
- Outcome
- environmental impact (EI)e5
- Direction
- highere5
- Value
- > 23e5
- Comparator
- one-pass herbicide programse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e5“The two-pass herbicide programs had higher environmental impact (EI) (> 23) than the one-pass herbicide programs (< 15)”
Claim · model-written summary
Imazethapyr followed by or tank-mixed with glyphosate had environmental impact equivalent to one-pass programs.
- Taxon
- soybeanGlycine maxt0
- Treatment
- imazethapyr was followed by or tank-mixed with glyphosatee6
- Outcome
- EIe6
- Direction
- equivalente6
- Value
- ∼ 14e6
- Comparator
- one-pass herbicide programse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e6“except when imazethapyr was followed by or tank-mixed with glyphosate, which had an equivalent EI (∼ 14) to the one-pass herbicide programs”
Claim · model-written summary
Gross margins were highest for treatments that included glyphosate.
- Taxon
- soybeanGlycine maxt0
- Treatment
- treatments that included glyphosatee7
- Outcome
- gross marginse7
- Direction
- higheste7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e7“gross margins were highest for treatments that included glyphosate”
Claim · model-written summary
Glyphosate plus imazethapyr was the best alternative to a sequential two-pass glyphosate program.
- Taxon
- soybeanGlycine maxt0
- Treatment
- glyphosate + imazethapyre7
- Outcome
- best alternativee7
- Direction
- best alternativee7
- Comparator
- sequential two-pass glyphosate programe7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e7“glyphosate + imazethapyr was the best alternative to a sequential two-pass glyphosate program”
Claim · model-written summary
A combination of glyphosate with another mode of action would be most beneficial for soybean weed management.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- a combination of glyphosate with another mode of actione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e7“a combination of glyphosate with another mode of action would be most beneficial”
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321 papers in the same direction as this paper · 112 in the opposite direction · 26 reporting no difference from an alternative
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See all 460 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.