Termination

Termination is an important factor in planning and executing your cover crop. Cultural, chemical, and mechanical options are available to terminate cover crops prior to planting the next cash crop; below is the latest information from around the Midwest. Please see the bottom of the page for information on  important nitrogen management concerns and planting green.

Managing Cover Crop Profitably (SARE Handbook Series Book 9) by Andy Clark (2007, 3rd ed.) is a good resource for getting started with cover crops.


Strategies/Timing

To the right is the different strategies for timing cover crop termination. It is generally preferable to start with Plan A, though other plans may be better suited to specific purposes or unfavorable weather conditions. See the full NRCS zone map here.

Termination types

Important Nitrogen Management Concerns

We recommend applying starter N at planting for corn, especially when considerable cover crop residue is present. Most cover crops are early users of soil-available nitrogen, so starter N can offset this early immobilization.

Cover crop residue with a high carbon to nitrogen (C:N) ratio can further reduce soil N availability to meet a corn crop’s high N demand. Grasses and cover crop mixes with grasses have a high C:N ratio, making it very important to add starter N in these systems or to sidedress N early in the season. The cover crop’s maturity and species (and the weather) will affect N availability for the growing cash crop.

Planting Green

Planting green is a term used when producers plant a cash crop directly into a standing cover crop that is still green. In such cases, producers typically terminate the cover crop within a day or two before or after planting. Consider this method a higher management option that will require you to adapt as weather and environmental conditions change. Planting green is generally much better adapted and beneficial for soybeans than corn.

Advantages:

  • Increases biomass for weed control
  • Utilizes excessive moisture during wet years
  • Reduces evaporation, erosion, and nutrient loss because of increased biomass
  • Increases photosynthesis and the release of root exudates as food for soil biology
  • Increases habitat for beneficial organisms
  • Improves planter performance in cover crops past the vegetative growth stage because you are working in a standing crop vs. a thick, rubbery mat

Disadvantages:

  • Increases habitat for pests
  • Increases the risk of wrapping on planter drives and wheels; hairpinning; potential stand reduction
  • Pollen shed plugs breathers or air flow devices on equipment
  • Potentially depletes soil moisture under dryer conditions
  • Increases N immobilization

Planting Green Management Considerations:

  • Ensure sufficient planting depth and seed slot closure
  • You may need to change spoked row cleaners and closing wheels on the planter because of wrapping from the additional cover crop residue
  • You will need to increase Ni in starter fertilizer for crops like corn and grain sorghum
  • Provide extra protection from pollen on your equipment’s radiators and air intakes
  • Provide extra protection for drive chains on planters or drills
  • Consider GPS guidance, which can be a major advantage over row markers

Articles to Get Started