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Weed Management Tactics in Organic No-Till

Posted: September 8, 2009

Use cover crops to grow your own mulch right where it will be used to suppress weeds for your crops!
Planting soybeans into a rye cover crop flattened with a roller/crimper. (Photo by Matt Ryan)

Planting soybeans into a rye cover crop flattened with a roller/crimper. (Photo by Matt Ryan)

Vigorous cover crops that produce large amounts of vegetation, or biomass, are vital for organic no-till crop management. Hairy Vetch is a great over-wintering legume cover crop that can be terminated in the spring. Cereal Rye is a farmer-favorite in the northeast because it can be planted later than any other cover crop and produces relatively large amounts of biomass.

Cover Crop Biomass

  • Test your Soil Fertility, and if necessary, amend with compost or manure to promote healthy growth of cover crops.
  • Increase your Cover Crop Seeding Rate when growing cover crops that will be used for mulch in organic no-till crops.
  • Use an earlier cover crop Seeding Date for small grain cover crops.
  • Irrigation may be helpful to ensure successful and uniform establishment after seeding cover crops.

Mulch Uniformity

  • Think ahead about Direction of Planting. Drill small grain cover crops perpendicular to the direction you intend to roll them down. Then be sure to plant your cash crop in the same direction as the cover crop was rolled.
  • If you can’t sow perpendicular, try combining Broadcast and Drill Seeding by spinning some of the cover crop seed onto the soil before you drill it.

Soybean Canopy
Soybean growth mid-season. (Photos by Matt Ryan)

Cash Crop Competitiveness

  • Try Matching Fertility Needs of cover and cash crops. Match nitrogen loving crops such as corn with legume cover crops like hairy vetch. Hairy vetch is a poor cover crop for soybean because it will provide available nitrogen that will disproportionally benefit weeds over the crop. Likewise, don’t plant cereal rye before corn because it will immobilize nitrogen in the soil, making corn plants more susceptible to weed competition.
  • Increase your Seeding Rate to make crop plants more weed suppressive.
  • Adjust planting equipment to provide appropriate Seed Placement and Seed-Soil Contact when planting cash crops.
  • Monitor for Early-Season Pests and be prepared to apply appropriate tactics and to replant sections if damage is too severe.

Prepared by Matt Ryan, Dave Mortensen, and Bill Curran

Contact Information

William S. Curran
  • Professor of Weed Science
Phone: 814-863-1014