Abstract
Abstract The success of dicamba-tolerant soybean [ Glycine max (L.) Merr.] has revived concerns about plant growth regulator (PGR) herbicide exposure to conventional soybean. In laboratory studies, soybean root nodulation is inhibited by excess auxin, which is the mechanism of action of PGR herbicides. Soybean exposed to PGRs in a field environment may have a similar response, and if nodulation is compromised, nitrogen (N) fixation may be reduced, with subsequent seed yield or protein content decreases. Many soybean–N studies report minimal impact to soybean yield. However, if soybeans show foliar PGR injury symptoms, could N application compensate for a potential nodulation inhibition response? This study examined the response of non–PGR tolerant soybean to N after exposure to low doses of 2,4-D and dicamba applied once (at soybean growth stages V1, V3, and early reproduction [R1 or R2]) or twice (V1 + V3 or V3 + R). N was either foliar or soil applied at early (∼5 d after PGR application) or late (10 d after PGR application) timings. Nodulation and plant growth were evaluated at R3, and grain yield and seed protein and oil content were quantified at maturity. Plant biomass and nodulation were reduced by 10% with some PGR treatments, and early foliar N application after PGR injury resulted in reduction up to 25%. N applications to non–PGR treated soybean did not increase yield. Soybean treated with PGR at V1 or V3, with or without N, had yields similar to control treatments. However, yield reductions of up to 20% were observed when PGRs were applied at V5 or R stages or when double PGR applications were followed by early foliar N application. Seed protein and oil content were not affected by PGR or N treatment.
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Claims 10
Claim · model-written summary
Some PGR treatments reduced soybean biomass by 10%.
- Taxon
- soybean
Glycine maxe1 - Treatment
- some PGR treatmentse0
- Outcome
- Plant biomasse0
- Direction
- reducede0
- Value
- 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant biomass and nodulation were reduced by 10% with some PGR treatments”
e1“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
Some PGR treatments reduced soybean nodulation by 10%.
- Taxon
- soybeanGlycine maxe1
- Treatment
- some PGR treatmentse0
- Outcome
- nodulatione0
- Direction
- reducede0
- Value
- 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant biomass and nodulation were reduced by 10% with some PGR treatments”
e1“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
Early foliar nitrogen following PGR injury reduced soybean biomass by up to 25%.
- Taxon
- soybeanGlycine maxe2
- Treatment
- early foliar N application after PGR injurye0
- Outcome
- Plant biomasse1
- Direction
- reductione0
- Value
- up to 25%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“early foliar N application after PGR injury resulted in reduction up to 25%”
e1“Plant biomass and nodulation were reduced by 10% with some PGR treatments”
e2“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
Early foliar nitrogen following PGR injury reduced soybean nodulation by up to 25%.
- Taxon
- soybeanGlycine maxe2
- Treatment
- early foliar N application after PGR injurye0
- Outcome
- nodulatione1
- Direction
- reductione0
- Value
- up to 25%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“early foliar N application after PGR injury resulted in reduction up to 25%”
e1“Plant biomass and nodulation were reduced by 10% with some PGR treatments”
e2“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
Nitrogen did not increase yield without PGR treatment.
- Taxon
- soybeanGlycine maxe0
- Treatment
- N applicationse0
- Outcome
- yielde0
- Direction
- did not increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N applications to non–PGR treated soybean did not increase yield.”
Claim · model-written summary
PGR treatment at V1 or V3 yielded similarly to controls, regardless of nitrogen.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- PGR at V1 or V3, with or without Ne0
- Outcome
- yieldse0
- Direction
- similare0
- Comparator
- control treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean treated with PGR at V1 or V3, with or without N, had yields similar to control treatments.”
Claim · model-written summary
PGR application at V5 or reproductive stages reduced soybean yield by up to 20%.
- Taxon
- soybeanGlycine maxe1
- Treatment
- PGRs were applied at V5 or R stagese0
- Outcome
- yielde0
- Direction
- reductionse0
- Value
- up to 20%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“yield reductions of up to 20% were observed when PGRs were applied at V5 or R stages”
e1“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
Double PGR application followed by early foliar nitrogen reduced yield by up to 20%.
- Taxon
- soybeanGlycine maxe1
- Treatment
- double PGR applications were followed by early foliar N applicatione0
- Outcome
- yielde0
- Direction
- reductionse0
- Value
- up to 20%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“yield reductions of up to 20% were observed when PGRs were applied at V5 or R stages or when double PGR applications were followed by early foliar N application”
e1“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
PGR and nitrogen treatments did not affect seed protein content.
- Taxon
- soybeanGlycine maxe1
- Treatment
- PGR or N treatmente0
- Outcome
- Seed proteine0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed protein and oil content were not affected by PGR or N treatment.”
e1“soybean [ Glycine max (L.) Merr.]”
Claim · model-written summary
PGR and nitrogen treatments did not affect seed oil content.
- Taxon
- soybeanGlycine maxe1
- Treatment
- PGR or N treatmente0
- Outcome
- oil contente0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed protein and oil content were not affected by PGR or N treatment.”
e1“soybean [ Glycine max (L.) Merr.]”
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See all 62 papers →8 of 13 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.