Cover Crop Selection

Cover crops are being widely promoted and slowly adopted. Farmers don’t doubt the benefits covers play in soil health, but often question the economic prospects of planting one and if there will be a return.



Since cover crops are still the exception, here are seven reasons to plant cover crops. 

1.       Cover crops can help you implement a no-till system.

2.       Cover crops can help reduce erosion by improving aggregate stability.

3.       Cover crops support soil microbial activity.

4.       Cover crops can help with weed control. 

5.       Cover crops help build soil organic matter.

6.       Cover crops can reduce the need for commercial fertilizers.

7.       Cover crops can extend the grazing season for livestock.

As with any new practice, you want to do everything possible to make it successful. Selecting what will work best with your operation will support your decision to use cover crops. Often, we hear suggestions that you should first decide what you want the cover crop to do, but that may be difficult as one of my clients said, “I want it to do everything.”



One of the big things to focus on is to increase soil microbial activity. Soil microbes drive the soil system.  The more microbes we have, the more we release nutrients, and the more we promote aggregate stability. There are many microbial products on the market, but why not grow your own? Multispecies mixes will best support microbial activity. Each species added to the mix promotes different microbes.  Five or more species would be considered ideal. Nitrogen-fixing species should be part of the mix, too. There can be pitfalls to growing a lot of different crops so you might want to consider something simpler to start with.



Extending your grazing season sounds simpler. Lots of producers like to graze turnips in the wintertime.  This a good choice because the cattle love them. Ideally, turnips should be planted by early September.  How do you do this? Fly them on or use a high clearance applicator adapted to seeding. Sounds expensive? Maybe you can start with cereal rye or triticale drilled after harvest. Both are suitable for winter grazing and both are also suitable for green chopping in the spring.



Maybe you want to start by growing your own nitrogen. Legumes are the way to go. Crimson clover, red clover and hairy vetch are popular choices. One traditional way to use clover is to plant it in a small grain crop in spring. Then after harvesting the grain, let it grow out for hay. Next spring, once again it needs to grow into May to maximize nitrogen production. Hairy vetch or clover may be planted into soybeans aerially or by high clearance equipment by September 1. It should also grow into May to maximize nitrogen fixed and stored in the soil for the next corn crop.    



If you want to open your no-till ground to increase water infiltration and improve root penetration, you may want to try oilseed radishes or annual ryegrass or maybe both. Radishes experience winter-kill, so that is a bonus. Annual ryegrass can be difficult to kill, so work out how you plan to terminate it in spring.



Some producers like to keep it simple by planting cereal rye or triticale after corn. Soybeans can be planted or drilled either before or after termination. A simple cover after soybeans is oats and radish. It winter-kills and can be easy to plant into in spring. Oats and radish should be flown on or planted into early maturity beans after harvest.



Consider soil health testing to provide yourself with some scientific data to prove that you are accomplishing what you want to with cover crops. Run a before test and another maybe two or three years down the road, and notice the difference you will see.



There are way too many options to cover them all in this short blog. Michigan State University maintains the Midwest Cover Crop Tool, which is a good place to start when picking your species of cover crop to plant. Don’t be afraid of choosing a more complicated mix, but do your homework on how to make it work. Contact us at rpmsoils.com 

Zombie Weed Apocalypse

By: W Kevin Nelson, CCA 4R NMSSenior Agronomist, Prairie Agronomics, LLC 

The growing season of 2019 just keeps on giving. Without going over all the morbid details, let’s just say that it’s been challenging from the very beginning, and looks like the challenges will continue on through to harvest and beyond.

As we get into the latter part of summer we are still contending with weeds that have refused to die. For lack of a better term, zombie weeds. These weeds have had burndown herbicide treatments, pre-emergent residual treatments, one or more post treatments, and still refuse to die. Some are newly emerged, some have just not succumbed to the programs we had planned before the spring weather went off the tracks. And now they have gone to seed, or soon will.

At this point, another spray trip becomes little more than an attempt at revenge. The plants are way above label size restrictions, and have hardened off with the dry conditions of the last few weeks. The chances are they won’t die, and the seed on them is probably already viable to bring on the next generation.

Am I going to give you the solution to the zombie weed apocalypse? Probably not. But I’ll point out that this weed control disaster isn’t a failure in any one program or system. We can find fields under all types of management that is experiencing problems, owing mainly to the conditions of the growing season. What I will say is this: start right now addressing the weed problems that will probably be coming our way in 2020.

Since many, though not all, weed control systems now combine seed traits with herbicide products, now is the time to start putting those combinations together. These systems must start with variety and hybrid selection, and seed companies will be on your doorstep early this fall. Choose a system that fits your needs from a production standpoint as well as weed control ability.

Consider cover crops to suppress weeds this fall. Some cover crop mixtures are better than others at keeping weeds down, and the consideration on how to terminate these crops needs to be factored in. Seed supplies may be an issue, as well.

Talk to your retailer about a fall burndown treatment. This can make a tremendous difference in weed pressure in the spring. With what looks like an extended harvest, it is crucial that you make your plans and let your retailer know with plenty of time what you intend to do.

So as you look out over your fields, frustrated with the zombie weeds poking through your crops or covering your Prevented Planting acres, remember that they aren’t coming after your brains, but you will need to put your brain to work now to prepare to hold them in check in the coming seasons.

Cover Crops and USDA.

In past years, using cover crops and crop insurance had sometimes been in conflict.  These issues had been addressed, but USDA recently came out with new guidelines that clear things up and seem to fit into most management situations.  It you go to the USDA cropland page  and look on the left side of the page to click on the Cover Crops Termination Guidelines, you will get a download that tells you all the rules.

Responsible Nutrient Management

We have spent the past three days at the National No-Till Conference in St. Louis.  Not only is this a great No-Till Conference, but it is a great crop production conference.

At the Luncheon on the first day, Responsible Nutrient Management Practitioners we awarded for their diligence in taking care of their soil nutrient levels.  Jason Carter, Mike Werling, and Mike Taylor were recognized for their nutrient management programs.  Jason Carter is using chicken litter to build his soils up.  His program also includes annual soil testing to measure progress.  As his soil has improved, he has cut back on chicken litter.

Mike Werling is looking at economics and applying fertilizer at modest rates to maximize profits.  He soil tests every three years.  Cover cr ops are also a component of his program.  Werling uses less than one pound per bushel of corn to produce high yields economically.

Mike Taylor makes sure his soil tests correlate with soil types on his farm.  He also uses cover crops and lower than average fertilizer rates to produce higher than average yields.  He uses variable rate technology as appropriate and also applies in row fertilizer to spoon feed his crops.  He is using No-till and cover crops to improve organic matter levels on the topsoil.

Planting Corn in Cereal Rye Cover Crop

We have seen issues with planting corn into cereal rye cover crops.  I have always thought that killing the cereal rye early could help.  Researchers at Iowa State University have found that cereal rye supports the growth of microbes that can be damaging to corn seedlings.  They found that earlier kills worked better.  They also suggest that nitrogen at planting time can help promote healthier corn plants.  We have also found that with low soil test sulfur, rye can create a sulfur deficiency.  Sulfur at planting is also a good idea.  See what they say about reducing the risk of corn seedling disease and yield loss after cereal rye.

Carbon Nitrogen Ratios

Carbon Nitrogen Ratios were studied at University of Nebraska to see how much nitrogen is contributed to the next year's crop.  It is interesting that in looking at Carbon Nitrogen Ratios in cover crops that it appears that a high tonnage crop like cereal rye may actually contribute more nitrogen than a legume crop that fixes nitrogen from the air.  I would like to do some in season nitrogen testing to confirm this, but it looks interesting enough to pass along for consideration.

Turbo-Till Seeder

Seeding cover crops effectively can be an issue.  I have seen the results from the Turbo-till Seeder with a seeding attachment.  Stands are nice and even with good emergence.  It seems to work better than vertical tillage after broadcasting seed.

Iowa Cover Crops

My Iowa reporter sent the photographs below of cover crops in Iowa.

Cereal Rye

Cereal Rye

Oats and Radish

Oats and Radish

Fall Weed Control

I have written several times on fall weed  control.  Early on, I failed to see the value.  With resistant weeds and heavy pressure, fall weed control is making sense to me at this point.  One fall weed control technique is to use fall applied herbicide.  A residual herbicide will not only supress the winter annuals, but i will also give some early spring control.  Use herbicides if you have n ot planned on cover crops.

The second technique of course it to use cover crops.  Weed suppression will last well into the growing season, and I have seen very good results.  You may still be able to get cereal rye seed to sow on fields that are going to soybeans next spring.  If this is your first time to use cover crops, I do not recommend planting corn into cereal rye.  I have one customer who is planning to do so, but he has done a lot of research on the subject before taking the plunge.

No-till Farmer says Weed Control and Soil Health go Hand in Hand.  

Herbicides and Cover Crops

Cover Crops are a great way to improve your soil health and enhance your weed control.  Issues with using cover crops include the ability to plant them in a timely manner and the ability to get a reasonable stand.  One of the factors standing in the way of a good stand is what residual herbicide have you used on the current crop.  No-till Farmer writes about Corn and Soybean Herbicides and Rotation to Cover Crops .  They say that for most herbicides, you should not have a problem.

Soil Health Partners

Soil Health Partnership is a farmer led movement to promote use of cover crops.  Yesterday on the last day of the Farm Progress Show in Boone IA, the corporate sponsors announced a committeemen of $4 Million over the coming years to support the group.  Their goals include establishing research protocols to support cover crops.

Cover Crop Time

If you have not planned your cover crop strategy for the fall, now is the time to think about what you want to do and get set up to do it.  This Prairie Farmer article gives some ideas.

The easiest to do is cereal rye after corn in fields where you are going to soybeans.  Corn planted in to cereal rye is not for beginners, although I know some people who are doing it.

In thinking about cover crops, set your goals in order to decide what ti plant.  Midwest Cover Crops Tool can help in decision making.

Cover crops can help with weed control, improve tilth, build organic matter, and help implement No-Till.

Cover Crop survey

I did not realize how long it has been since I posted.  We are putting the finishing touches on winter work.  Planning to head to the field tomorrow.

No-Till Farmer is trying to get people to complete a cover crops survey.

Contrasting Cover Crop Presentations

Last week, I heard contrasting presentations on cover crops.  Emerson Nafziger made a presentation in Litchfield on Wednesday.  He looked at research from several years of data on cover crops.  In his presentation he looked mainly for yield increases, and he did not find any.  It reminded me of  presentations on No-Til in the late 80's and early 90's.  He seemed to be missing the point.  Cover crops are a long term proposition and short term benefit can be difficult to assess.

Anthony Yannarell presented his research in Champaign on Saturday.  Unlike many researchers who prefer to look at yes or no answers, Yannarelll was looking into the why of cover crops and their weed control effect.  He used red clover in his research and found that leaving the entire plant on the surface was most effective in weed control,  One of the real benefits of cover crops is the weed control I am seeing.  While the weed control may not pay off in yield, hopefully you are getting some savings on herbicides.

Kill Annual Ryegrass Early

but not too early. Cover crops can be as easy to kill as having them freeze out, or as difficult to kill as Annual Ryegrass.  Many farmers I know have successfully planted soybeans into green cereal rye, but Annul Ryegrass is not so easy to get rid of.  Start by trying to kill it early.  It is too cold now. Wait until daytime temperatures are in the 50's so that some photosynthesis is taking place.  more details are available in a recent Prairie Farmer Article.

Cover Crops and Soil Health

Healthy Soils For Healthy Waters was the title of the Symposium that kicked off the Edge of Field Monitoring and Nutrient Management Conference.  The highlight of the whole conference was listening to David Brandt of Ohio discuss his system of cover crops and No-Till.  Brandt has been using cover crops for over 30 years.  His soils test very high for microbial respiration.  This indicates high microbial activity.  His figure of a $72 per acre net benefit to using cover crops is a  compelling reason to go for it.  I also had the privilege to visit with Brandt in person.  He talked a good bit about the benefits of using multiple cover crop species to enhance benefits.  He has tried as many as 12 species, but finds little addition benefit beyond using 8 species.

In an informal discussion over dinner, one of the Ohio State University professors in attendance indicated that he did not think that you could ever get enough nitrogen out of cover crops to have top yields.  Brandt disputed those remarks saying that he could raise 250 bushel per acre corn if he planted cover crops after harvesting wheat instead of going to double crop soybeans. Brandt is also experimenting with inter-seeding soybeans between corn rows for their nitrogen benefit.  The more we hear about cover crops, the more compelling it seems to use them,

Corn and Soybeans together?

Dave Brandt a leading Cover Crops advocate and farmer, is trying to grow soybeans as a nitrogen source on his farm.  He seeds the soybeans between the corn rows.  It is an interesting idea that Brandt says is working.  Read more in Farm Futures.

Cover crop Planting Time

We are fast approaching the end of the covercrop seeding time for many crops.  If you are flying one radish, annual ryegrass, or many other crops, now is the time.  The recent rain should be advantageous, especially if the seed is out there,  Cereal Rye can be planted as late as Thanksgiving, but if those fields will be planted to corn, be sure and kill it early in the spring.  Soybeans can be planted into rye more easily.

On the Fence about Cover Crops?

If you are still thinking about whether or not to plant cover crops this fall, it is decision time.  If you are deciding on species, The Midwest Cover Crops Council can help.  Species to choose depends on goals, desired planting method, desired kill method, and planned crop for 2016.  If you are deciding on fields, pick your least productive.  You are likely to get a quick response on poor ground. You need to get seed ordered now.  You need to figure out how you are going to plant now.  If you plan to fly seed on, you need to line up a flyer now.  We have seen some good results with cover crops including better weed control, better crop vigor, and excellent control of wind erosion.  

Soybeans Planted in Cover Crop

The soybeans below were planted early in a cover crop of Cereal Rye. The beans look excellent.  The weed control is excellent.  The producer likes to plant into green cover crop because he says the planter works better.  You can't argue with success.  This field is near Portage Des Sioux, Missouri.

Soybeans in Cover Crop