During this year’s 25th National No-Tillage Conference, one of the interesting hallway conversations dealt with the clash between a Purdue University weed scientist and organizations that sell or promote annual ryegrass as a cover crop.
As several no-tillers pointed out, Purdue weed scientist Bill Johnson is no fan of annual ryegrass and believes suppliers and some conservation groups oversell the weed control benefits of cover crops, especially annual ryegrass.
In a later phone conversation, Johnson told me his plot work indicates annual ryegrass is difficult to kill and that it has many of the same characteristics as weeds (dormancy and continued germination through the season, as well as a high propensity to develop herbicide resistance). He also feels it’s foolish to promote it as a cover crop when glyphosate-resistant annual ryegrass is likely already in Kentucky and other corn- and soybean-producing states.
Johnson feels annual ryegrass doesn’t help with control of summer annuals that emerge after a cover crop is terminated in the spring. However, he does recognize it works better with some winter annual weeds.
Annual ryegrass is definitely popular as this year’s No-Till Farmer benchmark study (pg. 42) found 28% of growers seeded it as a cover crop in 2016.
Tough on Annual Ryegrass
What really upset no-tillers was a 4-page report on “Cover Crop Do’s and Don’ts” that Purdue issued last summer. Co-authored by Johnson, the report’s weed management section contained the following statement:
“Don’t use annual ryegrass as a cover crop. Purdue Weed Science does not endorse planting annual ryegrass.”
After numerous phone calls, emails and letters from no-tillers and others promoting annual ryegrass-based conservation programs were sent to weed scientists and Purdue’s Dean of Agriculture, the report was removed from the university’s ag website.
Co-authored by 20 ag scientists, it was republished as a Crop Production Network regional report with no mention of annual ryegrass. However, growers were cautioned to avoid cover crops that are difficult to terminate or are contaminated with weed seeds.
No. 1 Choice
Mike Starkey no-tills 2,550 acres and cover crops 90% of that ground, using annual ryegrass on all but 10% of those cover cropped acres.
“We don’t have many weed concerns, but annual ryegrass suppresses the weeds we do have,” says Starkey. “It also scavenges nitrogen, improves our soil structure and aids in the movement of air and water in the soil.”
Starkey’s gripe is that several Purdue weed scientists maintain annual ryegrass should be treated as a weed, an attitude unfortunately adopted by some weed scientists in other states.
Starkey feels strongly that Purdue is undermining the role of annual ryegrass. Because of that, and the fact that he didn’t support funding for Purdue researchers who are not 100% behind Indiana’s conservation partnership, he resigned last summer as president of the Indiana Soil and Water Conservation District Assn.
Dan Towery feels Purdue has gone overboard with their objections to annual ryegrass. The owner of Ag Conservation Solutions in Lafayette, Ind., counts the Oregon Ryegrass Growers Commission among his clients. He maintains some Purdue folks rely too much on what they’ve learned from their own research plots, are not big believers in no-till and have refused opportunities to see how growers are making annual ryegrass work.
“Among other things, no-till and annual ryegrass offer a huge benefit with helping avoid weeds that come up from stirring the soil,” says Towery. “Annual ryegrass can help control weeds, but cereal rye will serve you better if this is your No. 1 need.”
Too Many Differences
This situation reminds me of a “Frank Comments” column I wrote in 2015 on the differences between on-farm results and university research. It listed 29 reasons why growers often get different results than university researchers. Visit no-tillfarmer.com/frank0215 to read this column.
No-tillers who have been successful with cover crops know there’s much more to controlling weeds than tillage and herbicides. What we need is more of a collaborative effort to enhance the value of no-till, cover crops, pest management and keeping something green growing on every acre every day.
