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Cowpea as a Cover Crop in Ohio

ANR-0128
Agriculture and Natural Resources
Date: 
04/05/2023
Sarah Noggle; Educator; Food, Agriculture, and Environmental Sciences; Ohio State University Extension, Paulding County
Rachel Cochran; Extension Associate, Water Quality; Food, Agriculture, and Environmental Sciences; Ohio State University Extension, Paulding County

Information gathered from the Midwest Cover Crops Council (MCCC) was used to compile this summary on how to use cowpea as a cover crop in Ohio. For more information, see the Midwest Cover Crops Field Guide, Third Edition, and the Cover Crop Selector Tool found at: midwestcovercrops.org/selector-tool/.Plants with one, small, white flower and long, hairless, leafless, light-green seed pods, and darker green, smooth-edged leaves.

Identification

  • Long taproot
  • Growth similar to soybean
  • Hollow, hairless stems
  • Hairless, smooth leaves that may be dull or shiny
  • Terminal leaflet that is usually longer than the lateral leaflets
  • Long, slender pods (3–6 inches) with 6–13 seeds per pod

Cultural Traits

  • Summer annual
  • Minimum germination temperature: 65 degrees Fahrenheit
  • Reliable establishment window (state average): June 10–Aug. 16
  • Semi-upright to climbing growth habit
  • Preferred soil pH: 5.5–6.5
Table 1. Rating the traits of cover crop cowpea.
Heat tolerance Excellent
Drought tolerance Excellent
Shade tolerance Good
Low fertility tolerance Excellent
Winter survival Winter-killed

Planting

  • Drilled at 1–1½ inches
    • 50–90 lb./acre (pure live seed)
  • Broadcast with shallow incorporation
    • 55–100 lb./acre (pure live seed)
  • Broadcast without incorporation

Additional planting information:

  • 3,600 seeds per lb.
  • Inoculation type: cowpeas, lespedeza.
  • When planting on slopes or using for forage/grazing, increase seeding rate.

Rules for Financial Assistance Program Recipients
Individuals participating in financial assistance programs are required to follow Natural Resources Conservation Service (NRCS) Appendix A regarding seeding rates and dates. Failure to do so will jeopardize payments. Appendix A can be found in Ohio’s Field Office Technical Guide, Section 4, Ecological Sciences Tools: efotg.sc.egov.usda.gov/#/state/OH/documents/section=4&folder=-6.

Performance

  • Dry matter = 2,500–4,500 lb. per acre, per year
    • Biomass quantity is highly dependent on planting/termination dates and precipitation.
  • Total nitrogen = 70–150 lb. of N per acre (not fertilizer replacement).
    • Plant early in the season (June) for full nitrogen potential.
    • Cowpea must be inoculated with the proper inoculant to increase nitrogen content.

Additional performance information:

  • Some cultivars are nematode resistant.
Table 2. Rating the attributes of cover crop cowpeas.
Nitrogen source Very good
Soil builder Good
Erosion fighter Good
Weed fighter Very good
Grazing Very good
Quick growth Very good
Lasting residue Good
Mechanical forage harvest Good
Grain seed harvest Good

Termination

  • Tillage
    • If terminating with only tillage, multiple passes are often required.
  • Chemical
  • Winterkill

Additional termination information:

  • Cowpea can compete with cash crop if not completely terminated.
  • Adjust termination dates based on soil moisture.
  • Follow NRCS guidelines for cover crop termination dates to comply with crop insurance.
Table 3. Potential advantages of cover crop cowpea.
Soil Impacts
Subsoiler Good
Frees phosphorus Good
Compaction fighter Very good
Allelopathic (produces biochemicals that inhibit weeds) Good
Chokes weeds Good
Other
Attracts beneficials Very good
Short windows Excellent

Potential Disadvantages

Increased insects/nematodes: could be a moderate problem

  • Host plant for soybean cyst nematode

Increased crop diseases: could be a moderate problem

Establishment challenges: occasionally a minor problem

  • Weak plant with low volunteer seed survivability

Contributors

This publication was adapted with consent from the Midwest Cover Crops Council (MCCC) with content from the Midwest Cover Crops Field Guide, Third Edition, and Cover Crop Selector Tool (midwestcovercrops.org/selector-tool/). It was created under a joint project with MCCC to produce customized introductory guidance about cover crops for all member states/provinces. Ohio cover crop recipes can be found at midwestcovercrops.org/statesprovince/ohio/.

The Midwest Cover Crops Council (midwestcovercrops.org) aims to facilitate widespread adoption of cover crops throughout the Midwest by providing educational/outreach resources and programs, conducting new research, and communicating about cover crops to the public.

Funding for this project was provided by the McKnight Foundation.

Red square with white lettering spelling McKnight Foundation.

 

 

Originally posted Apr 5, 2023.
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