Abstract
Field studies were conducted on Sharkey clay soil (very‐fine, smectitic, thermic Chromic Epiaquert) at Stoneville, MS (33°26′ N lat). The objectives were to determine the effect of application of 0 and 35 kg N ha −1 applied early in the growing season to glyphosate‐resistant (GR) and non‐GR soybean [ Glycine max (L.) Merr.] cultivars using two weed management systems in irrigated and nonirrigated environments. Weed management systems were (i) pre‐emergent followed by postemergent weed management using nonglyphosate herbicides applied to both GR and non‐GR cultivars (PRE + POST) and (ii) postemergent weed management using glyphosate on GR cultivars and nonglyphosate herbicides on non‐GR cultivars (POST). Applied N had no effect on weed management in or yield from soybean and lowered average net returns by $28 to $50 ha −1 . Average seed yields from the highest‐yielding GR cultivar in 1999 and 2000 were 135 and 270 kg ha −1 more than 1999 and 2000 yields from a non‐GR cultivar in the nonirrigated environment (all net returns were negative and yields <1500 kg ha −1 ). In the irrigated environment, use of a non‐GR cultivar compared with a GR cultivar resulted in a significant 200 and 250 kg ha −1 greater yield and greater profits in 2 of 3 yr. Use of PRE + POST compared with POST‐only was not necessary for achieving greatest yield or net return with either non‐GR or GR cultivars. Use of postemergent glyphosate always resulted in the cheapest weed control ($43 to $81 ha −1 ), even with the greater cost for seed of GR cultivars included. There was no measured effect of glyphosate compared with nonglyphosate herbicides on GR cultivar yield.
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Claims 11
Claim · model-written summary
Applied nitrogen had no effect on weed management.
- Taxon
- soybean
Glycine maxe0 - Treatment
- Applied Ne0
- Outcome
- weed managemente0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applied N had no effect on weed management in or yield from soybean”
Claim · model-written summary
Applied nitrogen had no effect on soybean yield.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Applied Ne0
- Outcome
- yield from soybeane0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applied N had no effect on weed management in or yield from soybean”
Claim · model-written summary
Applied nitrogen reduced average net returns by $28 to $50 ha −1.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Applied Ne0
- Outcome
- average net returnse0
- Direction
- lowerede0
- Value
- $28 to $50 ha −1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applied N had no effect on weed management in or yield from soybean and lowered average net returns by $28 to $50 ha −1”
Claim · model-written summary
The highest-yielding GR cultivar exceeded a non-GR cultivar by 135 and 270 kg ha −1 in nonirrigated 1999 and 2000 trials.
- Taxon
- SoybeanGlycine maxt0
- Material
- highest‐yielding GR cultivare0
- Outcome
- Average seed yieldse0
- Direction
- more thane0
- Value
- 135 and 270 kg ha −1e0
- Comparator
- non‐GR cultivare0
- Setting
- nonirrigated environmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Average seed yields from the highest‐yielding GR cultivar in 1999 and 2000 were 135 and 270 kg ha −1 more than 1999 and 2000 yields from a non‐GR cultivar in the nonirrigated environment”
Claim · model-written summary
Net returns were negative in nonirrigated comparisons.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- net returnse0
- Direction
- negativee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“all net returns were negative and yields <1500 kg ha −1”
Claim · model-written summary
Nonirrigated yields were below 1500 kg ha −1.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- yieldse0
- Direction
- <e0
- Value
- 1500 kg ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“all net returns were negative and yields <1500 kg ha −1”
Claim · model-written summary
Non-GR cultivars yielded 200 and 250 kg ha −1 more than GR cultivars under irrigation.
- Taxon
- SoybeanGlycine maxt0
- Material
- non‐GR cultivare0
- Outcome
- yielde0
- Direction
- greatere0
- Value
- 200 and 250 kg ha −1e0
- Comparator
- GR cultivare0
- Setting
- irrigated environmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“In the irrigated environment, use of a non‐GR cultivar compared with a GR cultivar resulted in a significant 200 and 250 kg ha −1 greater yield”
Claim · model-written summary
Non-GR cultivars provided greater profits in two of three irrigated years.
- Taxon
- SoybeanGlycine maxt0
- Material
- non‐GR cultivare0
- Outcome
- profitse0
- Direction
- greatere0
- Value
- 2 of 3 yre0
- Comparator
- GR cultivare0
- Setting
- irrigated environmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“In the irrigated environment, use of a non‐GR cultivar compared with a GR cultivar resulted in a significant 200 and 250 kg ha −1 greater yield and greater profits in 2 of 3 yr.”
Claim · model-written summary
PRE + POST management was unnecessary for greatest yield or return relative to POST-only.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- PRE + POSTe0
- Outcome
- greatest yield or net returne0
- Direction
- not necessarye0
- Comparator
- POST‐onlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Use of PRE + POST compared with POST‐only was not necessary for achieving greatest yield or net return with either non‐GR or GR cultivars.”
Claim · model-written summary
Postemergent glyphosate produced the cheapest weed control, at $43 to $81 ha −1.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- postemergent glyphosatee0
- Outcome
- weed controle0
- Direction
- cheapeste0
- Value
- $43 to $81 ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“Use of postemergent glyphosate always resulted in the cheapest weed control ($43 to $81 ha −1 )”
Claim · model-written summary
Glyphosate and nonglyphosate herbicides had no measured difference in GR cultivar yield.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- glyphosatee0
- Outcome
- GR cultivar yielde0
- Direction
- no measured effecte0
- Comparator
- nonglyphosate herbicidese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Soybean”
e0“There was no measured effect of glyphosate compared with nonglyphosate herbicides on GR cultivar yield.”
The same questions in other papers
glyphosate · yield · Glycine max (soybean)Results differ
67 papers in the same direction as this paper · 55 reporting no difference from an alternative
- positive
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- no effect
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See all 123 papers →nitrogen · weed · Glycine max (soybean)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- positive
- positive
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nitrogen · yield · Glycine max (soybean)Positive and negative results
97 papers in the same direction as this paper · 318 in the opposite direction
- positive
- no effect
- positive
412 papers more in this group
See all 416 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.