Abstract
A field experiment was conducted in 1998 and 1999 at Keiser, AR, to evaluate glyphosate timing and soybean population in reducing hemp sesbania and pitted morningglory interference with dryland and irrigated glyphosate-resistant soybean under a narrow row, no-till production system. Soybean densities following emergence were 247,000, 475,000, and 729,000 plants/ha. Glyphosate was applied at 0.56 kg ai/ha at the V2; V4; V2 and V4; and V2, V4, and R2 stages of soybean. In dry portions of the growing season, glyphosate increased moisture availability for dryland soybean because of control of hemp sesbania and pitted morningglory. As soybean population increased from 247,000 to 729,000 plants/ha, pitted morningglory and hemp sesbania control increased from 60 to 91%, respectively, for the V2 glyphosate application. Control of both species at 14 wk after emergence was at least 90% following the V4 alone treatment and sequential applications, with no differences in control among soybean populations. Untreated, irrigated hemp sesbania produced up to 32 million seeds/ha in 1999. Irrigation did not influence pitted morningglory seed production either year, and untreated pitted morningglory produced a maximum of 1 million seeds/ha in 1998 at 247,000 soybean plants/ha. Three sequential applications of glyphosate reduced pitted morningglory seed production to 9,000 seeds/ha and eliminated hemp sesbania seed production. Soybean yielded 1,297 kg/ha greater under irrigated than dryland conditions, whereas increasing soybean density from 247,000 to 729,000 plants/ha resulted in 416 kg/ha improvement in seed yield. At the densities of pitted morningglory and hemp sesbania present in this study, seed yield of drill-seeded soybean can be maximized following a V4 alone treatment or sequential glyphosate applications.Nomenclature: Glyphosate; hemp sesbania, Sesbania exaltata (Raf.) Rybd. Ex A. W. Hill #3 SEBEX; pitted morningglory, Ipomoea lacunosa L. # IPOLA; soybean, Glycine max (L.) Merr. ‘Delta King 5961 Roundup Ready®’.Additional index words: Light interception, soil moisture, transgenic soybean, weed competition.Abbreviations: DAE, days after emergence; PAR, photosynthetically active radiation; WAE, weeks after emergence; WAT, weeks after treatment.
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Claims 13
Claim · model-written summary
Glyphosate increased moisture availability for dryland soybean during dry periods by controlling weeds.
- Taxon
- soybean
Glycine maxe0 - Treatment
- glyphosatee0
- Interactor
- hemp sesbaniae0weed
- Second interactor
- pitted morningglorye0weed
- Outcome
- moisture availabilitye0
- Direction
- increasede0
- Qualifier
- In dry portions of the growing seasone0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In dry portions of the growing season, glyphosate increased moisture availability for dryland soybean because of control of hemp sesbania and pitted morningglory.”
Claim · model-written summary
Increasing soybean density increased pitted morningglory control under V2 glyphosate.
- Taxon
- soybeanGlycine maxe0
- Treatment
- soybean population increased from 247,000 to 729,000 plants/hae0
- Interactor
- pitted morningglorye0weed
- Outcome
- pitted morningglorye0
- Direction
- increasede0
- Value
- 60e0
- Qualifier
- V2 glyphosate applicatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As soybean population increased from 247,000 to 729,000 plants/ha, pitted morningglory and hemp sesbania control increased from 60 to 91%, respectively, for the V2 glyphosate application.”
Claim · model-written summary
Increasing soybean density increased hemp sesbania control under V2 glyphosate.
- Taxon
- soybeanGlycine maxe0
- Treatment
- soybean population increased from 247,000 to 729,000 plants/hae0
- Interactor
- hemp sesbaniae0weed
- Outcome
- hemp sesbania controle0
- Direction
- increasede0
- Value
- 91%e0
- Qualifier
- V2 glyphosate applicatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As soybean population increased from 247,000 to 729,000 plants/ha, pitted morningglory and hemp sesbania control increased from 60 to 91%, respectively, for the V2 glyphosate application.”
Claim · model-written summary
V4 glyphosate alone and sequential treatments gave at least 90% control of both weeds after 14 weeks.
- Taxon
- soybeanGlycine maxe0
- Treatment
- V4 alone treatment and sequential applicationse0
- Outcome
- Control of both speciese0
- Value
- at least 90%e0
- Qualifier
- at 14 wk after emergencee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Control of both species at 14 wk after emergence was at least 90% following the V4 alone treatment and sequential applications, with no differences in control among soybean populations.”
Claim · model-written summary
Weed control after V4 or sequential glyphosate applications did not differ among soybean populations.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- controle0
- Direction
- no differencese0
- Comparator
- soybean populationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“with no differences in control among soybean populations.”
t0“Soybean (Glycine max)”
Claim · model-written summary
Untreated irrigated hemp sesbania produced up to 32 million seeds per hectare in 1999.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- hemp sesbaniae0weed
- Outcome
- hemp sesbania producede0
- Value
- up to 32 million seeds/hae0
- Qualifier
- Untreated, irrigatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Untreated, irrigated hemp sesbania produced up to 32 million seeds/ha in 1999.”
t0“Soybean (Glycine max)”
Claim · model-written summary
Irrigation did not influence pitted morningglory seed production.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Irrigatione0
- Interactor
- pitted morningglorye0weed
- Outcome
- pitted morningglory seed productione0
- Direction
- did not influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irrigation did not influence pitted morningglory seed production either year”
t0“Soybean (Glycine max)”
Claim · model-written summary
Untreated pitted morningglory produced at most one million seeds per hectare in 1998.
- Taxon
- soybeanGlycine maxe0
- Interactor
- pitted morningglorye0weed
- Outcome
- pitted morningglory producede0
- Value
- 1 million seeds/hae0
- Qualifier
- at 247,000 soybean plants/hae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“untreated pitted morningglory produced a maximum of 1 million seeds/ha in 1998 at 247,000 soybean plants/ha.”
Claim · model-written summary
Three glyphosate applications reduced pitted morningglory seed production to 9,000 seeds per hectare.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Three sequential applications of glyphosatee0
- Interactor
- pitted morningglorye0weed
- Outcome
- pitted morningglory seed productione0
- Direction
- reducede0
- Value
- 9,000 seeds/hae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Three sequential applications of glyphosate reduced pitted morningglory seed production to 9,000 seeds/ha”
t0“Soybean (Glycine max)”
Claim · model-written summary
Three glyphosate applications eliminated hemp sesbania seed production.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Three sequential applications of glyphosatee0
- Interactor
- hemp sesbaniae0weed
- Outcome
- hemp sesbania seed productione0
- Direction
- eliminatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Three sequential applications of glyphosate reduced pitted morningglory seed production to 9,000 seeds/ha and eliminated hemp sesbania seed production.”
t0“Soybean (Glycine max)”
Claim · model-written summary
Irrigated soybean yielded 1,297 kg per hectare more than dryland soybean.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- irrigatede0
- Outcome
- yieldede0
- Direction
- greatere0
- Value
- 1,297 kg/hae0
- Comparator
- dryland conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean yielded 1,297 kg/ha greater under irrigated than dryland conditions”
Claim · model-written summary
Increasing soybean density from 247,000 to 729,000 plants per hectare improved yield by 416 kg per hectare.
- Taxon
- soybeanGlycine maxe0
- Treatment
- increasing soybean density from 247,000 to 729,000 plants/hae0
- Outcome
- seed yielde0
- Direction
- improvemente0
- Value
- 416 kg/hae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing soybean density from 247,000 to 729,000 plants/ha resulted in 416 kg/ha improvement in seed yield.”
Claim · model-written summary
The authors recommend V4 alone or sequential glyphosate applications to maximize drill-seeded soybean yield at the studied weed densities.
- Taxon
- soybeanGlycine maxe0
- Treatment
- V4 alone treatment or sequential glyphosate applicationse0
- Interactor
- pitted morningglorye0weed
- Second interactor
- hemp sesbaniae0weed
- Outcome
- seed yield of drill-seeded soybean can be maximizede0
- Qualifier
- At the densities of pitted morningglory and hemp sesbania present in this studye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At the densities of pitted morningglory and hemp sesbania present in this study, seed yield of drill-seeded soybean can be maximized following a V4 alone treatment or sequential glyphosate applications.”
The same questions in other papers
glyphosate · yield · Glycine max (soybean)Results differ
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- no effect
- positive
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See all 123 papers →glyphosate · soil: physics · Glycine max (soybean)Results agree
1 paper in the same direction as this paper
- positive
irrigation · yield · Glycine max (soybean)Positive and negative results
263 papers in the same direction as this paper · 72 in the opposite direction · 7 reporting no difference from an alternative
- no effect
- negative
- negative
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See all 343 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.