Abstract
Summer leguminous cover crops can improve soil health and reduce the economic and environmental costs associated with N fertilizers. However, adoption is often constrained by poor weed suppression compared to nonlegume cover crops. In field experiments conducted in organic vegetable cropping systems in north-central New York, two primary hypotheses were tested: (1) mixtures of legume cover crops (cowpea and soybean) with grasses (sorghum–sudangrass and Japanese millet) reduce weed seed production and increase cover crop productivity relative to legume monocultures and (2) higher soil fertility shifts the competitive outcome in favor of weeds and nonlegume cover crops. Cover crops were grown either alone or in grass–legume combinations with or without composted chicken manure. Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 ). Under more typical temperature and rainfall conditions in 2006, cowpea mixtures with Japanese millet stimulated cowpea biomass production and nodulation compared to monoculture, but soybeans were suppressed in mixtures with both grasses. Composted chicken manure shifted competition in favor of weeds at the expense of cowpea (2005), stimulated weed and grass biomass production (2006), and suppressed nodulation of soybean (2006). In a complementary on-farm trial, cowpea mixtures with sorghum–sudangrass suppressed weed biomass by 99%; however, both common purslane and hairy galinsoga produced sufficient seeds (600 seeds m −2 ) to replenish the existing weed seedbank. Results suggest that (1) mixtures of cowpeas with grasses can improve nodulation, lower seed costs, and reduce the risk of weed seed production; (2) soybean is not compatible with grasses in mixture; and (3) future costs of weed seed production must be considered when determining optimal cover crop choices.
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Claims 17
Claim · model-written summary
cowpea cover crops were severely suppressed under hot, dry 2005 conditions.
- Taxon
- cowpea
Vigna unguiculatae0 - Interactor
- weedse0weed
- Outcome
- severely suppressede0
- Direction
- suppressede0
- Qualifier
- Under hot, dry conditions in 2005e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 )”
Claim · model-written summary
soybean cover crops were severely suppressed under hot, dry 2005 conditions.
- Taxon
- soybean
Glycine maxe0 - Interactor
- weedse0weed
- Outcome
- severely suppressede0
- Direction
- suppressede0
- Qualifier
- Under hot, dry conditions in 2005e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 )”
Claim · model-written summary
cowpea cover crops were severely suppressed under hot, dry 2005 conditions.
- Taxon
- cowpeaVigna unguiculatae0
- Interactor
- sorghum–sudangrass
Sorghum
Sorghum ×drummondiie0other - Outcome
- severely suppressede0
- Direction
- suppressede0
- Qualifier
- Under hot, dry conditions in 2005e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 )”
Claim · model-written summary
soybean cover crops were severely suppressed under hot, dry 2005 conditions.
- Taxon
- soybeanGlycine maxe0
- Interactor
- sorghum–sudangrassSorghumSorghum ×drummondiie0other
- Outcome
- severely suppressede0
- Direction
- suppressede0
- Qualifier
- Under hot, dry conditions in 2005e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 )”
Claim · model-written summary
Low legume biomass and poor nodulation accompanied suppression in 2005.
- Taxon
- cowpea and soybeanGlycine maxVigna unguiculatae0
- Outcome
- low legume biomass, poor nodulatione0
- Direction
- lowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 )”
Claim · model-written summary
Powell amaranth seed production exceeded 25,000 seeds per square metre in 2005.
- Taxon
- cowpea and soybeanGlycine maxVigna unguiculatae0
- Interactor
- Powell amaranthe0weed
- Outcome
- Powell amaranth seed productione0
- Direction
- highe0
- Value
- > 25,000 seeds m −2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under hot, dry conditions in 2005, cowpea and soybean cover crops were severely suppressed by weeds in monoculture and by sorghum–sudangrass in mixtures, resulting in low legume biomass, poor nodulation, and high levels of Powell amaranth seed production (> 25,000 seeds m −2 )”
Claim · model-written summary
Cowpea mixtures with Japanese millet stimulated cowpea biomass and nodulation relative to monoculture in 2006.
- Taxon
- cowpeaVigna unguiculatae0
- Treatment
- cowpea mixtures with Japanese millete0
- Interactor
- Japanese millet
Echinochloa frumentaceae0other - Outcome
- cowpea biomass production and nodulatione0
- Direction
- stimulatede0
- Comparator
- monoculturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under more typical temperature and rainfall conditions in 2006, cowpea mixtures with Japanese millet stimulated cowpea biomass production and nodulation compared to monoculture, but soybeans were suppressed in mixtures with both grasses.”
Claim · model-written summary
Soybeans were suppressed in mixtures with both grasses in 2006.
- Taxon
- soybeansGlycine maxe0
- Interactor
- both grassese0other
- Outcome
- suppressede0
- Direction
- suppressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under more typical temperature and rainfall conditions in 2006, cowpea mixtures with Japanese millet stimulated cowpea biomass production and nodulation compared to monoculture, but soybeans were suppressed in mixtures with both grasses.”
Claim · model-written summary
Composted chicken manure shifted competition toward weeds and away from cowpea in 2005.
- Taxon
- cowpeaVigna unguiculatae0
- Treatment
- Composted chicken manuree0
- Interactor
- weedse0weed
- Outcome
- competition in favor of weeds at the expense of cowpeae0
- Direction
- in favor of weedse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Composted chicken manure shifted competition in favor of weeds at the expense of cowpea (2005), stimulated weed and grass biomass production (2006), and suppressed nodulation of soybean (2006).”
Claim · model-written summary
Composted chicken manure stimulated weed and grass biomass in 2006.
- Taxon
- cowpeaVigna unguiculatae0
- Treatment
- Composted chicken manuree0
- Interactor
- weedse0weed
- Outcome
- weed and grass biomass productione0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Composted chicken manure shifted competition in favor of weeds at the expense of cowpea (2005), stimulated weed and grass biomass production (2006), and suppressed nodulation of soybean (2006).”
Claim · model-written summary
Composted chicken manure suppressed soybean nodulation in 2006.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Composted chicken manuree0
- Outcome
- nodulation of soybeane0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Composted chicken manure shifted competition in favor of weeds at the expense of cowpea (2005), stimulated weed and grass biomass production (2006), and suppressed nodulation of soybean (2006).”
Claim · model-written summary
Cowpea and sorghum–sudangrass mixtures suppressed weed biomass by 99% on farm.
- Taxon
- cowpeaVigna unguiculatae0
- Treatment
- cowpea mixtures with sorghum–sudangrasse0
- Interactor
- weede0weed
- Outcome
- weed biomasse0
- Direction
- suppressede0
- Value
- 99%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a complementary on-farm trial, cowpea mixtures with sorghum–sudangrass suppressed weed biomass by 99%; however, both common purslane and hairy galinsoga produced sufficient seeds (600 seeds m −2 ) to replenish the existing weed seedbank.”
Claim · model-written summary
Common purslane produced seeds sufficient to replenish the weed seedbank.
- Taxon
- cowpeaVigna unguiculatae0
- Interactor
- common purslanee0weed
- Outcome
- seedse0
- Direction
- sufficiente0
- Value
- 600 seeds m −2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a complementary on-farm trial, cowpea mixtures with sorghum–sudangrass suppressed weed biomass by 99%; however, both common purslane and hairy galinsoga produced sufficient seeds (600 seeds m −2 ) to replenish the existing weed seedbank.”
Claim · model-written summary
Hairy galinsoga produced seeds sufficient to replenish the weed seedbank.
- Taxon
- cowpeaVigna unguiculatae0
- Interactor
- hairy galinsogae0weed
- Outcome
- hairy galinsoga produced sufficient seedse0
- Direction
- sufficiente0
- Value
- 600 seeds m −2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a complementary on-farm trial, cowpea mixtures with sorghum–sudangrass suppressed weed biomass by 99%; however, both common purslane and hairy galinsoga produced sufficient seeds (600 seeds m −2 ) to replenish the existing weed seedbank.”
Claim · model-written summary
The authors suggest cowpea and grass mixtures can improve nodulation, lower seed costs and reduce weed seed risk.
- Taxon
- cowpeasVigna unguiculatae0
- Outcome
- mixtures of cowpeas with grasses can improve nodulation, lower seed costs, and reduce the risk of weed seed productione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results suggest that (1) mixtures of cowpeas with grasses can improve nodulation, lower seed costs, and reduce the risk of weed seed production; (2) soybean is not compatible with grasses in mixture; and (3) future costs of weed seed production must be considered when determining optimal cover crop choices.”
Claim · model-written summary
The authors conclude soybean is incompatible with grasses in mixtures.
- Taxon
- soybeanGlycine maxe0
- Outcome
- soybean is not compatible with grasses in mixturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results suggest that (1) mixtures of cowpeas with grasses can improve nodulation, lower seed costs, and reduce the risk of weed seed production; (2) soybean is not compatible with grasses in mixture; and (3) future costs of weed seed production must be considered when determining optimal cover crop choices.”
Claim · model-written summary
The authors recommend accounting for future weed seed production costs when choosing cover crops.
Verbatim
e0“Results suggest that (1) mixtures of cowpeas with grasses can improve nodulation, lower seed costs, and reduce the risk of weed seed production; (2) soybean is not compatible with grasses in mixture; and (3) future costs of weed seed production must be considered when determining optimal cover crop choices.”
e1“cowpea and soybean cover crops”
The same questions in other papers
fertilization · symbiosis · Glycine max (soybean)Positive and negative results
49 papers in the same direction as this paper · 142 in the opposite direction
- positive
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See all 192 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.