Cover Crop Burn Down/Termination

Cereal Rye / Winter Triticale

  • Aaron Hager, University of IL/Hartzler, Iowa State University – “Glyphosate is the standard herbicide used for terminating cover crops.  Glyphosate is recommended at 0.63 lb a.e./A (18 oz Roundup PowerMax) for cereal rye 16 inches or less in height, and at higher rates for larger rye.  Tank-mixing other herbicides with glyphosate may reduce the activity of glyphosate.   Control of cereal rye with glyphosate was reduced up to 50% when tank-mixed with atrazine or Canopy, whereas 2,4-D, dicamba or Sharpen had little or no effect on rye control (K. Bradley, Univ. Missouri).  The antagonism observed with tank-mixes was greater with late applications than applications made to small rye.  Avoid spraying in the early morning or evening during periods with less than optimum temperatures.  The glyphosate label provides great flexibility in application rate.   While the Roundup PowerMax label states an 18 oz rate for cereal rye, this rate should only be used under ideal conditions.   Increase the rate when tank-mixing with other products, with larger rye, or when applications are made during cool periods.”
  • Liz Bosak, University of WI – “A general rule of thumb for termination of cereal rye with herbicides is to target the application before it reaches 18 inches in height. There are a few termination methods for cereal rye outlined in the fact sheet including rolling-crimping, mowing, and applying herbicides. For the no-till soybean research fields planted with a cereal rye cover crop, typically we use glyphosate and 2,4-D ester (0.5 lb ai/A) seven days before planting to terminate the rye. Otherwise, glyphosate (4.5 lb ae per gal, 22 fl oz/A) will terminate the winter grasses: rye, barley, triticale, and wheat.

 

Crimson Clover / Winter Peas – little info is out there…

  • Purdue – Crimson clover and Austrian winter peas are two popular legume species used as cover crops that typically do not winterkill and require a spring termination. Escapes and failed control of crimson clover and Austrian peas have been documented as rare, so they pose less threat as potential weed species in production crops than annual ryegrass. Herbicide control data for these two species are limited; however, cover crop guides advise that herbicides easily control crimson clover and winter peas. Standard rates of glyphosate, 2,4-D, and combinations of glyphosate and 2,4-D should achieve acceptable termination of these cover crops species.
  • Penn State recommends using glyphosate and dicamba together or 2,4-D and dicamba:

Effectiveness of herbicides for control of selected legume cover crops 2

Balansa Clover – the only product recommended by anyone is glyphosate at 1 qt. per acre (using 4 lb. active ingredient / gal)

 

Red clover

  • Bill Curran, Penn State University – “An excellent herbicide program to terminate a red clover stand prior to planting corn is one pint of 2,4-D LVE and one pint of dicamba (Banvel or Clarity). Apply 2,4 D and/or dicamba 7 to 14 days prior to or 3 to 5 days after corn planting if corn seeds are planted at least 1.5 inches deep. Do not plant soybeans after dicamba application. Applying 1 to 2 pounds per acre of atrazine will help provide additional control of the red clover. Glyphosate or paraquat alone are not recommended to kill a legume such as red clover. No-till establishment of the following crop helps maintain more benefits of the cover crop, such as superior soil protection and moisture conservation, than if tillage is used. If tillage is used, it is important to realize that most conservation tillage tools such as chisel plows or disks are unlikely to completely kill the red clover and prepare a satisfactory seedbed.”

 

Hairy Vetch

  • Penn State University – “A good herbicide program to terminate hairy vetch is a mix of glyphosate and 2,4-D or dicamba. Glyphosate alone is not a recommended program to kill a legume such as hairy vetch since its performance is variable. Plant growth regulators such as 2,4-D and dicamba are effective but also require some delay (1–2 weeks) between application and corn planting to avoid corn herbicide injury. For faster dessication, use paraquat and 2,4-D or paraquat and atrazine. Several other herbicides may also help manage hairy vetch in corn without having to delay corn planting. The hairy vetch should be allowed to dry down for about 10–14 days to facilitate ease of planting. The threat of hair pinning of residue in the seed slot is greatest when no-till planting into a vetch cover that is dying but not dry and crisp. Monitor seeding depth of corn and that hairy vetch vines do not wrap around row cleaners.”  Again, gray chart from Penn State spells out the rates pretty good (see above).

Annual Ryegrass – click here for the best info out there

Turnips / Radish

  • From SARE, Managing Cover Crops Effectively – “Radish, mustard, and turnip can be killed using a full rate of paraquat (Gramozone), multiple applications of glyphosate, or glyphosate plus 1pt/acre 2, 4-D.”

Rapeseed

  • Very little published information out there.  Several industry folks suggest using 2,4-D, along with a stronger burndown option like Sharpen or Balance at common burndown rates for adequate control.  Glyphosate by itself will not control rapeseed very well.

Spring control