Tag Archives: burndown of cover crops

The Right Chemistry for Annual Ryegrass Termination

As mentioned in the last blog post, terminating annual ryegrass is a crucial step in the management of this cover crop. Here are some tips for making sure it’s done properly the first time:

1. Wait until the ryegrass has fully broken dormancy from the winter.

2. Apply in the daytime, when the temps are consistently above 55 degrees during the day. Best results occur when the soil temps are above 45 degrees. Apply during the day so as to give the plant a minimum of 4 hours of daylight – preferably in sunny weather…NOT with rain predicted – to absorb the herbicide (glyphosate).

3. Don’t scrimp on chemistry – apply glyphosate at 1.25-1.50 lb a.e./a with ammonium sulfate and surfactant before the end of April. Coming back again is both costly and risky…annual ryegrass can build a tolerance to glyphosate and you don’t want to tempt fate. Get it done right the first time.

Follow label directions carefully with respect to pH and mixing order. It is important when adding ammonium sulfate, buffering agents or water conditioners that they be added to the full spray tank of water and agitated for 3-5 minutes before adding the glyphosate. This is to ensure that the calcium, magnesium, iron and other dissolved minerals in the water do not interfere with the glyphosate activity.

5. Early termination of the cover crop makes control easier and reduces the amount of residue into which you’ll plant corn or soybeans. Early control also facilitates soil dry-down, allows for significant decomposition of annual ryegrass residue and release of nutrients for uptake by the corn or soybean crop.

6. Some growers have found it easier to plant into the annual ryegrass first and then apply a burndown. Warmer weather conditions improve glyphosate activity and planting into green vegetation has been successful, and is often easier than planting into a “half-dead” cover crop.

Annual Ryegrass Burndown this Spring

“An ounce of prevention is worth a pound of cure.” Benjamin Franklin’s quip is just as sound today as it was when uttered 250 years ago.

The reason annual ryegrass has NOT become a problem in the Midwest, despite heavy use in the past 20 years as a cover crop, is because those using it have been careful in its use…or have been able to recover from their mistakes without too much extra trouble or expense.

So, what can go wrong?

You let it grow too long in the spring before killing it with an effective “burndown” with glyphosate or other herbicide. Ideally, spray the crop before it gets to the “joint” stag (6 inches or so in top growth)

You try to spray the crop before all the grass is in active growth mode. It’s important to wait until it has fully broken dormancy, perhaps a week after you notice the first growth, and after the daytime temperatures reach 55 – 60 degrees, and nighttime temperatures are consistently above 40 degrees.

You’ve used a cover crop mix and thus the dates to spray become variable because each plant (annual ryegrass, cereal rye, vetch, clover) recover from dormancy at different times.

You spray once but don’t kill it all off with one application. At that point, it pays to be vigilant. Letting a cover crop recover from one application of herbicide can give it tolerance to a second application. Thus, it’s very important to pay attention to the second application, in terms of products to use, timing of the application and assuring that the second burndown is effective.

For more details, contact neighbors or a trusted agronomist. And by all means, check out this free information about controlling annual ryegarss, from our website.2016 ARG as a Cover Crop – 4 page

Annual Ryegrass Plugging Through another Winter

While the temperatures plunge and the snow whirls, annual ryegrass top growth has been dormant for months. But under the freeze, the annual ryegrass roots continue to flourish, adding depth, girth and mass to a system that builds healthy soil in numerous ways.

The depth of rooting alone is a benefit, because it opens channels in the soil profile. Those channels, next spring and summer, will allow corn roots to seek deeper veins of nutrition and moisture. Even in a dry year, corn that goes deep will continue to thrive. And, with any normal precipitation, those root channels will help the soil absorb the rainfall rather than allowing it to run off.

Annual ryegrass has an appetite for nitrogen, too, so it becomes a storehouse of nitrogen when it grows. Then, in the spring, after it is killed with herbicide (before planting corn or beans), the nitrogen stored in the residue becomes a fertilizer for the hungry corn plants. And the massive root structure of annual ryegrass, when it is killed, that mass degrades and decomposes, increasing the carbon content and organic matter in the soil, giving worms and microbiological organisms a food source.

Because of annual ryegrass’ nature to sequester nitrogen, it’s place in the crop rotation allows you to lighten up considerably on nitrogen inputs.

For more information about annual ryegrass, why it’s beneficial and how to manage it successfully as a cover crop, you can check out this free four-page management guide. Or you can click here to view a series of YouTube videos on the subject.

Trick or Treat – Annual Ryegrass as a Cover Crop Delivers Both

Growing a cover crop like annual ryegrass has immense benefits, as you have no doubt learned. Thus the “treat” this Halloween is in the form of tangible revenue that growers receive from annual planting of cover crops:

Improved soil conditions – without tillage, soil health continues to grow. With cover crops, that growth is accellerated
Fewer inputs – less tillage, fewer passes over the soil, less compaction and fewer dollars spent on fertilizers, like nitrogen
Deeper soil profile, opened up by the deep, penetrating roots of annual ryegrass, allows better access to moisture in dry years and migration of deeper layers of nutrients
More profit – when the soil is happy, crops are happier, and production increases.

The “trick” of annual ryegrass, as with any cover crop, is learning the details of new management techniques. The seeding of cover crops and the management of annual ryegrass in particular, in the spring, are very important. If managed poorly, annual ryegrass can become a pest, a weed. But as you learn the tricks, management becomes almost second nature.

For more information about growing and managing annual ryegrass, click here.

Annual Ryegrass and other Cover Crops – New Tips on Termination

Admittedly, this is late for the 2017 burndown season. And yet, it’s important to share while it’s topical…managing cover crops is a “growing” interest and we’ll keep an eye on posting an update early next year.

Mike Plumer is the key driver for this article, published a couple months ago by No-Till Farmer magazine. It was taken largely from a seminar Mike did at the National No-Till Conference in St. Louis, earlier in the year. Check out the whole article. It has great tips about managing burndown when the cover crop includes annual ryegrass in a “cocktail mix”. It also looks at the issue of annual ryegrass varieties, and how important it is to know the source of the seed. Different varieties emerge from winter dormancy, for example, which provides problems when trying to kill it in a timely fashion.

Finally, Mike’s discussion covers the subject of killing annual ryegrass once it has reached the “joint” stage or beyond, when control with generic glyphosate will not be enough. Click here to see the entire article.

Annual Ryegrass – Now What?

Ok, so now the annual ryegrass is killed. It’s residue will soon become worm food. The decaying roots will become added food for a rich soil biology. The channels left by the decayed roots will create more friability in the soil…crumbly, pliable, spacious. Moreover, new corn and soybean roots will be able to find their way deeper into the soil profile, where added moisture and nutrients can build a more productive crop this year.

Some who are now contemplating corn planing activity may wish to consider adding a next round of annual ryegrass within a short time thereafter. For years now, producers have been having success with “interseeding” annual ryegrass into their corn, when it is less than knee high (V4- V5 stage).

We will cover this subject more in the coming weeks, but for now you could take a look at the following publications, each covering aspects of the reasons, the methods and the benefits of planting a cover crop in the spring.

Penn State Extension Service article

Univ. of Minnesota Extension

Glyphosate and Monsanto Clear The Hurdle

An alternative health blogger known as Food Babe has been going toe to toe with Monsanto for years, trying to get traction with consumers on the dangers of glyphosate…Monsanto’s RoundUp.

She has postulated that glyphosate, even in minute traces per billion, causes cancer. But in a recent rebuttal from Snopes.com (an independent, myth-busting organization made up mainly of scientific journalists), they report that the scare tactics leveled by Food Babe are “FALSE”.

The federal EPA agency began looking at glyphosate in 1985, and by 1993 concluded it is carcinogenic. They talked about the herbicide’s ability to become waterborne and thus get into drinking water, as well as foods that live in soil exposed to glyphosate.

Since then, it was shown that studies linking cancer to glyphosate relied on concentrations of the chemical that were way out of proportion with amounts that are used in agricultural applications. Recent tests that show potentially adverse effects at lower exposures are also suspect, as peer review has raised questions about scientific methods and data validity.

In March of 2015, the World Health Organization’s International Agency for Research on Cancer said that glyphosate “may have some carcinogenic potential” but, the consensus among the world’s regulatory agencies, according to the Snopes.com article, is that glyphosate “is safe for consumption and non-carcinogenic at environmentally relevant levels.”

Consequently, the World Health Organization concluded: “Glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through the diet.”

Click here to review the Snopes.com article.

The Chemistry of Burndown of Annual Ryegrass

Glyphosate is the most common herbicide used to control annual ryegrass. It’s very important to use a rate that is adequate. The minimum rate of glyphosate recommended for annual ryegrass is 1.25-1.50 lb a.e./acre with ammonium sulfate and surfactant in late March to early April. Use 1.75 lb a.e./acre if needed.

Glyphosate products vary in concentration and this affects application rate. Here are two application examples to provide the necessary 1.25-1.50 lb/acre a.e.:

A 41% glyphosate product containing 3 lbs/gal of a.e. (acid equivalent). Application rate should be 53-64 oz/acre
Roundup PowerMax is a 48.7% glyphosate product with 4.5 lb/gal of a.e. Application rate should be 36-43 oz/acre

While one burndown application should provide control of the annual ryegrass, growers should plan for two applications, especially if the initial spray conditions were cool

Consider using an herbicide with a different mode of action if re-spraying is needed (Research is currently testing alternatives to glyphosate and tank mixes with glyphosate to reduce the dependence on this important herbicide)

Even when annual ryegrass is small it requires full rates of herbicides to achieve control. Low rates will often stress the plant making it more difficult to control at a later date

In years with marginal weather conditions, or where the ryegrass is in the jointing stage, use a higher rate of glyphosate (1.75 lb a.e./acre) to help insure complete control. Using a full label rate once is preferred to split applications of a lower rate.

Killing Annual Ryegrass Cover Crops Adds to Soil Organic Matter

Cereal rye is a great cover crop. Sometimes, however, the amount of biomass in the spring creates difficulty for drilling corn seed. The excess vegetation can impede proper planting and can also take moisture out of the soil that crops will need this summer.

Annual ryegrass doesn’t create as much biomass,The residual left by the annual ryegrass after burndown quickly decomposes into the no-till soil. It becomes food for soil critters and microorganisms. And the massive root network slowly decomposes too, building organic matter. The channels created by ryegrass roots become channels for corn roots. The combination of root channels and more organic matter allows better infiltration of rain. but it is important to spray the crop out in a timely fashion.

Corn roots in ARG 6-06 Starkey
Annual ryegrass, if let grow too long, can be more difficult to kill. And letting it go to seed is asking for trouble…nobody wants to contend with a cover crop that gets away.

Last week’s blog discusses the proper guidelines for applying herbicide to kill the cover crop. Here’s a linkto the management guide where those instructions are.

Terminating Annual Ryegrass Effectively – the 1st Time

The first important step in controlling annual ryegrass used as a cover crop is the timing of the burndown.

It is best done when the plant is small, 6-9” in height, and preferably before the first node has developed. Typically, this happens in late March to late-April depending on weather and farm location.

Make sure the crop is actively growing, so as to optimize the uptake of the herbicide (glyphosate).

Daytime minimum temperature should be at 55 degrees (F) and above 60 is better. • If night temperatures drop below 38, wait three days before spraying. • Soil temperatures should be above 45.

Early termination of the cover crop makes control easier and reduces the amount of residue into which you’ll plant corn or soybeans.

Early control also facilitates soil dry-down, allows for significant decomposition of annual ryegrass residue and release of nutrients for uptake by the corn or soybean crop.

Some growers have found it easier to plant into the annual ryegrass first and then apply a burndown. Warmer weather conditions improve glyphosate activity and planting into green vegetation has been successful, and is often easier than planting into a “half-dead” cover crop.

Warm temperatures and actively growing annual ryegrass plants are a must for effective control.

Use a thorough spray coverage using moderate spray pressure and a medium spray droplet size. Don’t use air induction spray systems or nozzles that produce coarse droplets.

The application rate should be about 8-12 gallons per acre.

Spray at least 4 hours prior to sunset to allow for maximum translocation of the glyphosate within the plant.

While one burn-down herbicide application often provides control of the annual ryegrass. Inspect the results and then be ready for a second application if needed. (If you use too weak an herbicide solution, it will make the plant more resistant and more difficult to control later.)

Apply glyphosate at 1.25-1.50 lb a.e./a with ammonium sulfate and surfactant. Follow label directions carefully with respect to pH and mixing order. It is important when adding ammonium sulfate, buffering agents or water conditioners that they be added to the full spray tank of water and agitated for 3-5 minutes before adding the glyphosate. Additional NIS surfactant, if called for, is normally added last.

Weather conditions affect how well glyphosate controls annual ryegrass and a second application may be required.