Blogging by the Bushel
With numerous challenges over the past several years for producers, we at Mercer Landmark understand the need for a comprehensive risk management solution. We seek to provide our customers with unparalleled service to ensure maximum results.

Archive for April, 2016

By: Ben Stoller

Cover crop termination time is here. Below are some recommendations from Ohio State, Purdue and Monsanto regarding best practices for timely and effective burndown of popular cover crop grasses:

General glyphosate (Roundup® PowerMAX) recommendations

  1. Wait for 4-5 days of consecutive >45°F temperatures before spraying.  Glyphosate is translocated within the plant, so warmer temperatures will enhance plant uptake.
  2. “Do not substitute citric acid for AMS.  They are not the same” (Dan Childs, Monsanto Weed Management TDR).

“…it is always recommended to use ammonium sulfate (AMS) to condition hard water. Using citric acid has become a popular replacement for AMS, but we would warn that citric acid lacks some of the desired characteristics of AMS. Citric acid does condition hard water by binding to magnesium and calcium molecules, but it lacks the ammonium or nitrogen source that helps the glyphosate move efficiently into the target plant and translocate to the grass meristem.” (pg. 4, Purdue Extension Bulletin WS-52-W)

Annual ryegrass recommendations

  1. Annual rye is more difficult to kill than cereal rye or winter wheat (Dr. Loux, OSU)
  2. Purdue University recommends a minimum of 1.25 pounds of acid equivalent of glyphosate for annual rye, which equates to 36 ounces of Roundup PowerMAX®.  Monsanto recommends 36-44 ounces of Roundup PowerMAX® for annual ryegrass.
  3. Dr. Loux at Ohio State recommends a minimum of 1.5# ae/ac, or 44 oz. /ac of Roundup PowerMAX®, even higher on larger plants or in cold weather.
  4. Purdue research has shown greatest consistency in 1.25#/ae (36 oz. Roundup PowerMAX®) plus 1 oz. of Sharpen (saflufenacil) in terminating annual rye at all application timings.  Sharpen must have methylated soybean oil (MSO) at 1% v/v and AMS.  Ask your Mercer Landmark agronomy representative about Destiny HC
  5. Adding metribuzin (Sencor, Dimetric, etc.) or atrazine may result in antagonism of glyphosate and result in annual rye termination failure (Purdue Extension Bulletin WS-52-W) (Dan Childs, Monsanto).

Cereal rye recommendations: .75#/ae of glyphosate, or 22 oz. of Roundup PowerMAX® up to 18 inches tall.  (Loux, CORN newsletter 2015-08) (Purdue Extension Bulletin WS-50-W).

Winter Wheat: 32-44 ounces of Roundup PowerMAX® up to 18 inches tall (Loux, OSU).

The following links to university bulletins have excellent recommendations:

https://www.extension.purdue.edu/extmedia/ws/ws-50-w.pdf

https://www.extension.purdue.edu/extmedia/WS/WS-52-W.pdf

http://agcrops.osu.edu/newsletter/corn-newsletter/early-termination-cover-crops

http://agcrops.osu.edu/newsletter/corn-newsletter/2015-08/burndown-cover-crops

Please contact your Mercer Landmark agronomy representative for assistance in a successful cover crop burndown program.