Abstract
Abstract Cover crops belonging to the Cruciferae , Gramineae , and Leguminoseae families, summer fallow, and annual weed cover were compared in weed control and effect on the next year's corn ( Zea mays L.) and sunflower ( Helianthus annuus L.) crops. Corn yields were increased if legumes were present in the cover crop. Some grass‐legume mixtures gave more weed control at lower seed costs than pure legumes, and corn following some mixtures yielded as much as corn following pure legumes. Annual Cruciferae gave satisfactory performance at very low seed costs. Corn following most cover crops yielded considerably more than corn following annual weed cover. Sunflower yields following the cover crops did not differ significantly. Corn but not sunflower following summer fallow showed retarded growth and lighter green foliage than after cover crops. The symptoms disappeared in mid‐summer, but corn ear moisture was high at harvest. Concentrations of 14 chemical elements in corn and sunflower indicated that, except in P, composition of both crops responded similarly to cover crops and summer fallow. P concentration in corn plants after summer fallow was lower than after cover crops.
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Claims 12
Claim · model-written summary
Legume cover crops increased subsequent corn yield.
- Taxon
- Corn
Zea mays subsp. mayse0
- Treatment
- legumese0
- Outcome
- Corn yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn yields were increased if legumes were present in the cover crop”
Claim · model-written summary
Some grass legume mixtures controlled more weeds at lower seed cost than pure legumes.
- Taxon
- corn
Zea mays subsp. mayst0
- Treatment
- grass‐legume mixturese0
- Outcome
- weed controle0
- Direction
- moree0
- Comparator
- pure legumese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Some grass‐legume mixtures gave more weed control at lower seed costs than pure legumes”
t0“next year's corn”
Claim · model-written summary
Corn yield after some mixtures matched that after pure legumes.
- Taxon
- corn
Zea mays subsp. mayse0
- Treatment
- mixturese0
- Outcome
- corn following some mixtures yieldede0
- Direction
- as much ase0
- Comparator
- pure legumese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn following some mixtures yielded as much as corn following pure legumes”
e1“grass‐legume mixtures gave more weed control at lower seed costs than pure legumes”
Claim · model-written summary
Annual Cruciferae performed satisfactorily at very low seed cost.
- Taxon
- corn
Zea mays subsp. mayse1
- Outcome
- satisfactory performancee0
- Qualifier
- very low seed costse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Annual Cruciferae gave satisfactory performance at very low seed costs”
e1“corn ( Zea mays L.) and sunflower ( Helianthus annuus L.)”
Claim · model-written summary
Corn following most cover crops yielded more than after annual weed cover.
- Taxon
- Corn
Zea mays subsp. mayse0
- Treatment
- most cover cropse0
- Outcome
- Corn following most cover crops yieldede0
- Direction
- considerably moree0
- Comparator
- annual weed covere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn following most cover crops yielded considerably more than corn following annual weed cover”
Claim · model-written summary
Sunflower yields did not differ significantly among cover crops.
- Taxon
- Sunflower
Helianthus annuuse0 - Treatment
- cover cropse0
- Outcome
- Sunflower yieldse0
- Direction
- did not differe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Sunflower yields following the cover crops did not differ significantly”
e1“sunflower ( Helianthus annuus L.)”
Claim · model-written summary
Summer fallow retarded corn growth and lightened foliage relative to cover crops.
- Taxon
- Corn
Zea mays subsp. mayse0
- Treatment
- summer fallowe0
- Outcome
- retarded growth and lighter green foliagee0
- Direction
- retardede0
- Comparator
- cover cropse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn but not sunflower following summer fallow showed retarded growth and lighter green foliage than after cover crops”
Claim · model-written summary
Sunflower did not show the growth and foliage symptoms after summer fallow.
- Taxon
- sunflower
Helianthus annuuse0 - Outcome
- retarded growth and lighter green foliagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Corn but not sunflower following summer fallow showed retarded growth and lighter green foliage than after cover crops”
Claim · model-written summary
The summer fallow symptoms disappeared by mid summer.
- Taxon
- Corn
Zea mays subsp. mayse1
- Outcome
- symptoms disappearede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The symptoms disappeared in mid‐summer”
e1“Corn but not sunflower following summer fallow showed retarded growth and lighter green foliage than after cover crops”
Claim · model-written summary
Corn ear moisture was high at harvest after summer fallow.
- Taxon
- corn
Zea mays subsp. mayse0
- Outcome
- corn ear moisturee0
- Direction
- highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“corn ear moisture was high at harvest”
Claim · model-written summary
Except for phosphorus, corn and sunflower elemental composition responded similarly to cover crops and fallow.
- Taxon
- corn and sunflower
Helianthus annuusZea mays subsp. mayse0
- Outcome
- composition of both cropse0
- Qualifier
- except in Pe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Concentrations of 14 chemical elements in corn and sunflower indicated that, except in P, composition of both crops responded similarly to cover crops and summer fallow”
Claim · model-written summary
Corn phosphorus concentration was lower after fallow than cover crops.
- Taxon
- corn
Zea mays subsp. mayse0
- Treatment
- summer fallowe0
- Outcome
- P concentratione0
- Direction
- lowere0
- Comparator
- cover cropse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P concentration in corn plants after summer fallow was lower than after cover crops”
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103 papers in the same direction as this paper · 104 in the opposite direction · 14 reporting no difference from an alternative
- no effect
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See all 222 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.