Abstract
Glyphosate-resistant (GR) alfalfa offers growers new options for weed control in alfalfa. One potential benefit of using GR alfalfa is increased longevity of an alfalfa stand under frequent harvests. It was hypothesized that GR alfalfa would have a greater longevity because of removal of weed interference with minimal crop injury. To study GR alfalfa yield, weed invasion, alfalfa stand persistence, and relative forage quality (RFQ), a field experiment with three weed control methods (no herbicide, glyphosate, and hexazinone) under two harvest frequencies (high and moderate) was established in August 2003 at the Michigan State University Agronomy Farm in East Lansing, MI. Forage yield of established alfalfa was not adversely affected by herbicide treatments. There were no differences in weed biomass between alfalfa treated with glyphosate and that treated with hexazinone, except in 2007. Average GR alfalfa stand density decreased approximately 90% (from 236 to 27 plant m −2 ), and yield decreased approximately 30% (from 11.04 to 7.87 Mg ha −1 ) during the 7-yr period (2004 to 2010) of the experiment. Stand density of GR alfalfa showed natural thinning during the 7-yr period regardless of harvest intensity or herbicide treatment. In most production years (4 out of 5 yr), relative forage quality of GR alfalfa was higher under a high-intensity harvesting system (4 to 5 harvests yr −1 ) than it was with a moderate intensity harvesting system (3 to 4 harvests yr −1 ). Relative forage quality was not affected by weed removal with herbicides in most years. Weed removal and harvest intensity in established GR alfalfa had no effect on stand persistence.
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Claims 9
Claim · model-written summary
Herbicide treatments did not adversely affect established alfalfa forage yield.
- Taxon
- alfalfa
Medicago sativae0 - Treatment
- herbicide treatmentse0
- Outcome
- Forage yielde0
- Direction
- not adversely affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Forage yield of established alfalfa was not adversely affected by herbicide treatments.”
Claim · model-written summary
Weed biomass did not differ between glyphosate and hexazinone treatments except in 2007.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- glyphosatee0
- Outcome
- weed biomasse0
- Direction
- no differencese0
- Qualifier
- except in 2007e0
- Comparator
- hexazinonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no differences in weed biomass between alfalfa treated with glyphosate and that treated with hexazinone, except in 2007.”
Claim · model-written summary
GR alfalfa stand density fell about 90% over seven years.
- Taxon
- alfalfaMedicago sativae0
- Material
- GR alfalfae0
- Outcome
- stand densitye0
- Direction
- decreasede0
- Value
- approximately 90%e0
- Qualifier
- from 236 to 27 plant m −2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Average GR alfalfa stand density decreased approximately 90% (from 236 to 27 plant m −2 ), and yield decreased approximately 30% (from 11.04 to 7.87 Mg ha −1 ) during the 7-yr period (2004 to 2010) of the experiment.”
Claim · model-written summary
GR alfalfa yield fell about 30% over seven years.
- Taxon
- alfalfaMedicago sativae0
- Material
- GR alfalfae0
- Outcome
- yielde0
- Direction
- decreasede0
- Value
- approximately 30%e0
- Qualifier
- from 11.04 to 7.87 Mg ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Average GR alfalfa stand density decreased approximately 90% (from 236 to 27 plant m −2 ), and yield decreased approximately 30% (from 11.04 to 7.87 Mg ha −1 ) during the 7-yr period (2004 to 2010) of the experiment.”
Claim · model-written summary
GR alfalfa stands thinned naturally regardless of harvest intensity or herbicide.
- Taxon
- alfalfaMedicago sativae0
- Material
- GR alfalfae0
- Outcome
- natural thinninge0
- Qualifier
- regardless of harvest intensity or herbicide treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stand density of GR alfalfa showed natural thinning during the 7-yr period regardless of harvest intensity or herbicide treatment.”
Claim · model-written summary
High-intensity harvest gave higher relative forage quality in four of five years.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- high-intensity harvesting system (4 to 5 harvests yr −1 )e0
- Outcome
- relative forage qualitye0
- Direction
- highere0
- Qualifier
- 4 out of 5 yre0
- Comparator
- moderate intensity harvesting system (3 to 4 harvests yr −1 )e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In most production years (4 out of 5 yr), relative forage quality of GR alfalfa was higher under a high-intensity harvesting system (4 to 5 harvests yr −1 ) than it was with a moderate intensity harvesting system (3 to 4 harvests yr −1 ).”
Claim · model-written summary
Herbicidal weed removal did not affect relative forage quality in most years.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- weed removal with herbicidese0
- Outcome
- Relative forage qualitye0
- Direction
- not affectede0
- Qualifier
- in most yearse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Relative forage quality was not affected by weed removal with herbicides in most years.”
t0“alfalfa”
Claim · model-written summary
Weed removal had no effect on GR alfalfa stand persistence.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- Weed removale0
- Outcome
- stand persistencee0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Weed removal and harvest intensity in established GR alfalfa had no effect on stand persistence.”
Claim · model-written summary
Harvest intensity had no effect on GR alfalfa stand persistence.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- harvest intensitye0
- Outcome
- stand persistencee0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Weed removal and harvest intensity in established GR alfalfa had no effect on stand persistence.”
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glyphosate · weed · Medicago sativa (alfalfa)Positive and negative results
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- positive
- positive
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25 papers in the same direction as this paper · 26 in the opposite direction
- positive
- positive
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See all 52 papers →herbicide · quality: grain · Medicago sativa (alfalfa)Positive and negative results
5 papers in the same direction as this paper · 3 in the opposite direction
- negative
- positive
- positive
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See all 9 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.