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Beans or peas "feeding" nitrogen to neighbor crops: does it work?
Sources (0)
Promising Some peer-reviewed or extension evidence, but limited, conditional or mixed.
Legumes can transfer some nitrogen to neighbors in the same season, but amounts are variable and often small; most benefit comes after residues decompose.
- Evidence of considerable C and N transfer from peas to cereals via direct root contact but not via mycorrhiza. Scientific Reports (2021).
- N2 fixation, N transfer and LER in grain legume–wheat intercropping (2024), PMC open access.
Mechanism
Rhizodeposition and root contact; residue breakdown later.
What the research found
- A pea–cereal study found N transfer mainly via direct root contact, not mycorrhiza (Scientific Reports 2021).
- Transfer is promoted by low soil N and suppressed by N fertilization; it varies with density (legume–wheat intercrop study, 2024).
Caveats
Do not count on in-season N from beans for heavy feeders like corn; fertilize based on soil tests.
How to try it
Rotate: plant heavy feeders after legumes, and return legume residue to the soil.
Other Promising pairings (4)
- French marigold as a cover crop for root-knot nematodes
- Collards as a trap crop for diamondback moth in cabbage
- White clover living mulch under cabbage and other brassicas
- Carrots and onions against carrot fly
Evidence summary checked 2026-10-14. We cite only peer-reviewed studies, university extension and USDA/ARS sources; results may differ in your region. Not professional advice.