Tag Archives: burndown of cover crops

Time to Terminate Annual Ryegrass Cover Crops

The fields may already be clear of snow. You may already be noticing that the annual ryegrass or other cover crops are starting to show life. Watch carefully and be vigilant about terminating the crop before the grass reaches the “joint” stage.

Here are a couple of timely resources to help you figure out the timing, the right chemicals, the right dosage and whether or not you need to spray again. It’s best to get it right with the first application but there is a plan B should the first spray application not do the trick.

Click here for a free management brochure about annual ryegrass.

Click here for a quick guide to successful burndown of annual ryegrass.

Click here to learn about the residual effect of herbicides on corn and beans.

Making a Nitrogen Bank Account with Ryegrass as a Cover Crop

Here’s how Eileen Kladivco put it: Even with well-managed corn and soybean production, there is always some leaching of nitrate that originates either from residual fertilizer N or from the natural decomposition of soil organic matter. Our annual cropping systems are “leaky” because there are long fallow periods between crop maturity in September and the active growth of the next cash crop in May. Most of the net downward flow of water to the drains occurs precisely during this long fallow period, when there is nothing to take up the nitrate.

Eileen is an agronomy department professor at Purdue University, a well-regarded researcher and teacher about soil and making agriculture more profitable. She goes on to say that, Non-legume cover crops will scavenge or “trap” soil nitrate that would otherwise move out of the rootzone into tile drains or groundwater. Cover crops actively take up nitrate during a portion of that fallow season, reducing the losses that occur to tile drains and recycling the nitrogen for later use. To read her Full article – click here.

In another publication, the author talked about the biomass of cover crops. Basically, he said that more biomass generally means more nutrients and organic matter returned to the soil.

The “plant available nitrogen” (PAN) released from a cover crop depends on what cover crop you’re growing and when you terminate the cover crop. As the cover crop plant matures, more nitrogen gets stored in the stems, so in general it’s best to terminate the cover crop before it reaches that stage. With annual ryegrass, terminating it before it reaches 6 or so inches in the spring is important…both to take advantage of the nitrogen available but also to keep the plant from reaching the joint stage.

As soil organisms decompose cover crop residues, part of cover crop is released as carbon dioxide. The rest decomposes and contributes to the soil organic matter…as well as giving up the stored nitrogen for the corn or beans maturing in the same soil.

The high price of nitrogen has growers looking for way to be more efficient. Using annual ryegrass may provide 60-80 lbs of nitrogen per acre. This alone could more than pay for the cost of the seed and planting the cover crop. For more information on annual ryegrass and its capacity as a nitrogen sink, click here.

Annual Ryegrass – a Christmas Gift that Keeps Giving

With snow covering a lot of the Midwest this month, cover crops like annual ryegrass have a good chance of wintering over. That means continued activity in the soil, even if the vegetative part of the plant is dormant.

Annual ryegrass roots can dig all winter long, extending to a couple of feet or more by springtime. In the winter, the roots permeate compacted soil and open it up for better water infiltration and biological activity. These are important aspects of soil health and crop production next summer.

Here’s a recent article on annual ryegrass and other cover crops, from the Farm Journal, that outlines some basics in choosing a cover crop, some tips on selecting varieties and a lot of encouragement to try it out…even on a small test plot, until you get the hang of the management changes necessary for adding cover crops on a big time basis.

Here are a couple of other resources about annual ryegrass, how to grow it, where to get it, and how to terminate it in the spring.

Mike Plumer – Granddaddy of Modern-day Cover Crop Advocacy

Back in the late 1980s and early 1990s, before we had met Mike Plumer, he already had more than a decade of advocacy and research into no-till farming and cover crops, especially annual ryegrass. At the time, Mike was an Extension Educator with the University of Illinois, a post he held for 34 years..

We, in Oregon, where 90 percent of the world’s ryegrass seed is grown, had no idea that Mike Plumer was about to give the industry of agriculture an immeasurable gift, while giving the annual ryegrass seed growers a new reason to get up in the morning.

Plumer, working with an innovative Hamilton County, Illinois farmer named Ralph “Junior” Upton, helped quantify the benefits of annual ryegrass in “siltpan” (Bluford) soil. Upton was concerned about the productivity on parts of his 1800 acre farm, where the compacted soil restricted the root growth of corn and soybeans. He wondered if going no-till and adding cover crops might improve productivity.

Plumer began testing on Upton’s farm and quickly discovered what we in Oregon didn’t know – that annual ryegrass roots grow through and permeate compacted soil. Better than that, the roots then extend downwards to a much as five feet, creating new pathways to moisture and nutrients for corn and bean crops to follow.

Since 2004, Upton has seen dramatic changes in his corn yields., according to a USDA profile on him. He says no-till saves him around $15 an acre. Using cover crops costs $8-$20 dollars an acre but it is well worth it. The amount of organic matter in Upton’s soils started at less than 1 percent (.81). That level is now up to 3 or 4 percent. “And that’s exactly what I needed for my soils on those fields,” Upton said.

Since then, Plumer has experimented all over the Midwest (as well as contributing to agriculture internationally) and become the best known cover crop advisor in the country. Below are a couple of very informative power point presentations developed by Plumer, which outline both the benefits and the precautions of annual ryegrass and other cover cropping system. Visit the annual ryegrass by clicking here.

Managing Annual Ryegrass

Cover Crops in Illinois: Why Use Them?

Feed the World? Feed the Soil First

The American Dust Bowl was a reminder about taking care of the soil. Yet here we are only 75 years beyond that deadly scourge and we find that the soil is still taken for granted.

Cover crops are an inexpensive way to replenish the soil. Here are some benefits to consider:

Keeping something green on the fields year ’round will keep the soil in place. Reduce or eliminate erosion. Reduce or eliminate topsoil being removed by wind. Annual ryegrass along the nation’s waterways would greatly reduce the dire problems in the Great Lakes, the Gulf of Mexico and many other places, because of agricultural runoff.

The roots of annual ryegrass penetrate deep into the soil, breaking up compaction, creating millions of channels that allow other crops to follow.

Corn roots can’t penetrate compaction. So, in dry years, corn suffers because the roots hit the compaction and then go laterally instead of deeper. Annual ryegrass roots extend to depths of 5 feet or more over the winter, passing right through compacted layers.
When ryegrass is killed off in the spring, the mass of roots becomes organic matter, food for all kinds of critters that live mostly below ground.
Once those channels open up, rainfall and snow melt can more easily be absorbed into the soil. Corn and other cash crops can find moisture and nutrients in deeper soil.

Cover crops, both the live plants and the decaying residue, are fodder for many life forms, including microorganisms, that are beneficial for soil health.

For more information about all these things, visit our website, or download a comprehensive guide to growing annual ryegrass.

Kill it Good…Annual Ryegrass is Your Friend until it Isn’t

Farmers have been successfully controlling annual ryegrass, as a cover crop in the Midwest, for more than 20 years. If somebody tells you “it’s a weed,” tell them politely, “Yes, I know, and it’s possible to control it if you know what you’re doing!”

Click here for our website page on successfully taking care of annual ryegrass in the spring.

Click here for our publication on Annual Ryegrass management Recommendations (2016 version)

burndown

Here are a few tips from those online sources:

Don’t let annual ryegrass stay around too long in the spring: kill it before the “joint” stage when the grass is between 4 and 8 inches tall. By now, the grass is active, so watch it carefully to optimize herbicide effectiveness
Wait for the right weather: daytime temps above 55 consistently; no rain, preferably spray earlier in the day to allow for maximum uptake by the plant before sundown and cooler temps
Use the right sprayer: don’t use a sprayer with coarse droplets
USE THE RATE LISTED ON THE LABEL. Don’t scrimp here. You don’t want the herbicide to fail, then have to battle annual ryegrass that comes back with more tolerance.
Spray again if you see any lingering color after a week. Use another herbicide with a different mode of action
Getting the pH of the water right is important: add ammonium sulfate with a surfactant to the water BEFORE adding the glyphosate to the tank.

Managing Annual Ryegrass as a Cover Crop

This past winter, annual ryegrass hardly went into dormancy….it was that mild. Of course, the value to the soil is multiplied in years like this, when ryegrass roots extend to depths of four or five feet.

Soon, it will be time to spay out the ryegrass, and it pays to do it right. Here are some tips for managing it properly. For more detail, click here.

Spray when the ryegrass has broken dormancy, and before it reaches 8 inches. Like lawn grass, if the cover crop looks long enough to mow, then it’s time to spray it with glyphosate.
Use a full rate of glyphosate in order to kill the grass on the first application. Keep an eye out to make sure it’s good and dead and spray again if there’s any regrowth
Wait for the right temperature and daylight to spray. Consistent daytime temps of above 55F is best. Gray, cloudy or rain…delay the spray.

Look at the website above for more details. And you can also download a free annual ryegrass management guide by clicking here.

Annual Ryegrass Management Guide – Comprehensive

Every year, the Oregon Ryegrass Commission updates its publications based on the prior year’s experience. We have updated two free annual ryegrass management guides for those using it as a cover crop.

The 4-page guide is more comprehensive. Click here.

The 2-page quick guide is perhaps more convenient, especially for those who know and use annual ryegrass already. Click here for that one.

In addition to new tips for planting and tips for killing the cover crop effectively, there are new precautions about use of residual herbicides, which can reduce or eliminate a cover crop if you’re not careful.

Cover Crops and Carbon Penalty

In a recent issue of Ag Web, sponsored by Farm Journal magazine, an article written by Darrell Smith covered some ideas and advice given by the magazine’s resident agronomist, Ken Ferrie. The following paragraphs caught my eye:

Cover crops can reduce corn yield by acting as weeds in the row and by tying up soil nutrients when they decompose. “If cover crop plants are allowed to grow in the corn row, the corn plants see them as weeds, and it creates stress,” Ferrie says. “Stress lowers yield potential. The longer weeds and corn plants grow together in the row, the greater the reduction in ear size. Even if you take out the weeds, or the cover crop, a few weeks later, the damage has been done. Yield potential has been lost, and you will never get it back.”

He goes on to say, “Another source of stress on young corn plants is the carbon penalty. When cover crops are killed, the influx of carbon in the residue leads to a higher population of soil microorganisms. They temporarily tie up soil nitrogen and other nutrients, leaving corn plants to go hungry in the critical early weeks. If a cover crop has a high carbon/nitrogen ratio, the longer it’s allowed to grow in the spring, the more residue and the higher the carbon penalty.”

This seems to make sense until you look at a couple of basics: In most cases, cover crops are planted in the fall, just after harvest or, increasingly, when the corn is still standing but already matured. (An exception is the relatively experimental “interseeding” of cover crops in the spring, after the corn is about knee high).Thus, the planting of a cover crop in August or September or October would have no bearing whatsoever on yield.

It appears that he may have planted another cover crop in the spring, because the fall planting had winter killed. Then,because of the bad spring weather (2014), he didn’t plant the corn until the end of May, six weeks after normal. He planted into a relatively new cover crop which, of course, would compete for available nitrogen. Then, as it turns out, he didn’t put any ‘starter’ nitrogen on the corn when he planted, but instead waited until weeks later when he sprayed glyphosate to kill the cover crop.

When he concludes that the reason for poor yield was because of “carbon penalty” (residue from dead cover crops creating more microorganisms and thus tying up nitrogen) it may in fact be more due to the anomalies in his experiment that year.

In any case, it’s important to remember to give corn plants a boost of nitrogen when planting – somewhere between 30 and 40 units. And if you’re planting into an existing cover crop, make sure you add the N then, not waiting until you burn down the cover crop, perhaps a month later.

Successful Tips for Cover Crops

In a recent article on Ag.com by Edith Munro, Dan Towery offered these tips for cover crop success.

Cover crop decisions can be initially overwhelming. “Details – especially timing – are critical,” says Dan Towery, president of Ag Conservation Solutions and Soil and Water Conservation Society.

Here are five questions and tips Towery gives to guide you if you are considering a cover crop.

1. What do you want to accomplish with a cover crop?
Cover crops offer a range of possible benefits that include:
• Reducing erosion.
• Reducing soil compaction.
• Scavenging nitrogen.
• Fixing nitrogen.
• Increasing organic matter.
• Improving weed control.
• Increasing water infiltration.
• Improving soil biological activity.
• Matching goals with cover crop selection is essential.

Selecting a maximum of three is the first step to narrowing the list of cover
crops to consider.

2. How will you plant it and when?
Planting method and timing are key interrelated decisions. Traditionally, the best seed-to-soil contact comes from drilling, but that must occur after harvest. In the Upper Midwest, seeding that late limits the cover crop options.

3. What will follow the cover crop in your rotation?
Since some cover crops tie up nitrogen, it is especially important to consider the carbon-to-nitrogen ratio of the covers being considered if the following crop will be corn.

4. Which cover crop will you plant?
Multiple options are available depending on location. Consider using the Midwest Cover Crop Council’s Cover Crop Decision Tool.

The tool provides customized guidance for Illinois, Indiana, Iowa, Michigan, Minnesota, North Dakota, Ohio, Ontario, and Wisconsin. It allows you to plug location, cash crop, planting and harvest dates, and cover crop objectives to narrow the list of cover crop choices that match your specific conditions.

Two books offer more detailed information:

Managing Cover Crops Profitably (Third Edition), published by the Sustainable Agriculture Research and Education program (sare.org)
Cover Crops Field Guide, from the Midwest Cover Crops Council.

5. How will you terminate your cover crop?
Towery recommends planning early and killing the tougher cover crops early. Some cover crops will winterkill on their own, and some may be easy to kill. Others may require following fairly specific instructions to terminate.

Once you have completed your initial research and have decided on a potential list of cover crops, Towery recommends planting a small trial plot to become familiar with various cover crop traits.

“It can be as small as 10×10 feet. Look for opportunities where you can watch how your cover crops do through a fall-winter-spring cycle,” he suggests. “A sweet corn patch is good, or if you have a small wheat or corn silage field.”

Success with cover crops requires a systems approach, Towery says. “The reason some growers can make cover crops work but their neighbors can’t isn’t complex. It’s all about attention to details and timing.

“Doing the homework minimizes unpleasant surprises. You must complete all the steps for success,” he says.