Abstract
Many farms use leguminous cover crops as a nutrient management strategy to reduce their need for nitrogen fertilizer. When they are effective, leguminous cover crops are a valuable tool for sustainable nutrient management. However, the symbiotic partnership between legumes and nitrogen fixing rhizobia is vulnerable to several abiotic and biotic stressors that reduce nitrogen fixation efficiency in real world contexts. Sometimes, despite inoculation with rhizobial strains, this symbiosis fails to form. Such failure was observed in a 14-acre winter cover crop trial in the Rio Grande Valley (RGV) of Texas when three legume species produced no signs of nodulation or nitrogen fixation. This study examined the role of nitrogen, phosphorus, moisture, micronutrients, and native microbial communities in the nodulation of cowpea (Vigna unguiculata L. Walp) and assessed arbuscular mycorrhizal fungi as an intervention to improve nodulation. Results from two controlled studies confirm moisture and native microbial communities as major factors in nodulation success. Micronutrients showed mixed impacts on nodulation depending on plant stress conditions. Nitrogen and phosphorus deficiencies, however, were not likely causes, nor was mycorrhizal inoculation an effective intervention to improve nodulation. Inoculation method also had a major impact on nodulation rates. Continued research on improved inoculation practices and other ways to maximize nitrogen fixation efficiency will be required to increase successful on-farm implementation.
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Claims 7
Claim · model-written summary
Three legume species showed no nodulation or nitrogen fixation in the Rio Grande Valley trial.
- Taxon
- legume speciese0
- Outcome
- no signs of nodulation or nitrogen fixatione0
- Setting
- Rio Grande Valley (RGV) of Texase1
Not reportedDirection
Verbatim
e0“three legume species produced no signs of nodulation or nitrogen fixation”
e1“in the Rio Grande Valley (RGV) of Texas”
Claim · model-written summary
Moisture was a major factor in nodulation success.
- Taxon
- cowpea
Vigna unguiculatae1 - Treatment
- moisturee0
- Outcome
- nodulation successe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results from two controlled studies confirm moisture and native microbial communities as major factors in nodulation success.”
e1“cowpea (Vigna unguiculata L. Walp)”
Claim · model-written summary
Native microbial communities were a major factor in nodulation success.
- Taxon
- cowpeaVigna unguiculatae1
- Interactor
- native microbial communitiese0other
- Outcome
- nodulation successe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results from two controlled studies confirm moisture and native microbial communities as major factors in nodulation success.”
e1“cowpea (Vigna unguiculata L. Walp)”
Claim · model-written summary
Micronutrient impacts on nodulation depended on plant stress conditions.
- Taxon
- cowpeaVigna unguiculatae1
- Treatment
- Micronutrientse0
- Outcome
- nodulatione0
- Qualifier
- depending on plant stress conditionse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Micronutrients showed mixed impacts on nodulation depending on plant stress conditions.”
e1“cowpea (Vigna unguiculata L. Walp)”
Claim · model-written summary
Nitrogen and phosphorus deficiencies were unlikely causes of nodulation failure.
- Taxon
- cowpeaVigna unguiculatae1
- Treatment
- Nitrogen and phosphorus deficienciese0
- Outcome
- nodulatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen and phosphorus deficiencies, however, were not likely causes, nor was mycorrhizal inoculation an effective intervention to improve nodulation.”
e1“cowpea (Vigna unguiculata L. Walp)”
Claim · model-written summary
Mycorrhizal inoculation did not effectively improve cowpea nodulation.
- Taxon
- cowpeaVigna unguiculatae1
- Treatment
- mycorrhizal inoculatione0
- Interactor
- arbuscular mycorrhizal fungie2symbiont
- Outcome
- nodulatione0
- Direction
- nor wase0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nor was mycorrhizal inoculation an effective intervention to improve nodulation”
e1“cowpea (Vigna unguiculata L. Walp)”
e2“assessed arbuscular mycorrhizal fungi as an intervention”
Claim · model-written summary
Inoculation method substantially affected nodulation rates.
- Taxon
- cowpeaVigna unguiculatae1
- Treatment
- Inoculation methode0
- Outcome
- nodulation ratese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation method also had a major impact on nodulation rates.”
e1“cowpea (Vigna unguiculata L. Walp)”
The same questions in other papers
inoculation · symbiosis · Vigna unguiculata (cowpea)Results differ
11 papers in the same direction as this paper · 57 in the opposite direction
- positive
- positive
- no effect
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See all 69 papers →mycorrhiza · symbiosis · Vigna unguiculata (cowpea)Positive and negative results
7 in the opposite direction
- positive
- positive
- positive
4 papers more in this group
See all 8 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.