Plant Cover Crops

Learning about the benefits of planting cover crops.

Types of Cover Crops

Prevented Planting Row Crop Acres – Which Cover Crops Can Help?

The following was originally posted on May 27, 2011 when the Eastern Corn Belt was suffering with severe flooding and wet conditions.  In 2013 the Upper Midwest – especially Iowa, Minnesota, and Wisconsin – is flooded and wet.  Many farmers are considering taking the crop insurance for prevented planting.  Even if it would stop raining – which does not appear will happen anytime soon – many farmers will not be in their fields for two weeks.  While locations are different, the recommendations below still apply.  Please keep the farmers in the Upper Midwest in your prayers; they need it!

For other options that might include growing cover crops for forages click here.

More rain tonight on already flooded fields create a tough situation for many Midwestern farmers.
More rain tonight on already flooded fields create a tough situation for many Midwestern farmers.

In 2010 there were wet spots in fields that were never planted,  so some ingenious farmers planted cover crops in those spots after they dried out.  Now in 2011 there are several entire fields that may not be planted to cash crops at all.  I have heard from two friends in Ohio that are working on plans to help northwest Ohio farmers know what to use on their prevented acres.

Maybe this is not an issue where you live.  I hope you never have to face a spring like this year in the Eastern Corn Belt, where many producers in Ohio, Indiana, Illinois, and Michigan are struggling to get their crops in the ground.  The forecast is for many more days of rain to finish out the month of May.

For wet spots in fields there are many good options like these cover crop radishes that were planted later in the season in a field of sweet corn.

For prevented planting the cover crops may not be harvested until after November 1st.

So what are the options for planting cover crops in the prevented planted fields?  Below I will list the options with a few of their benefits and also some disadvantages.

Oats

Advantages

  1. Provides erosion control
  2. Scavenges nitrogen
  3. Grows a deep and fibrous root mass
  4. Promotes mycorrhiza growth
  5. Quick to establish
  6. Relatively inexpensive
  7. Can be broadcast and lightly tilled in
  8. Can be added to other cover crops to add additional value
  9. Can spray with broadleaf herbicides if necessary to control weeds

Disadvantages

  1. While they provide cover and decent root growth they do not provide additional nitrogen to the soil (at the most it would be very minimal)
  2. Best to use seed oats vs. bin run oats for optimum value
  3. If planting wheat after oats there may be some “grass after grass” issues (I’m not confident this will be a problem and would welcome comments)

 

Field Peas or Austrian Winter Peas

Austrian Winter Peas and cover crop radishes were planted into prevented planting acres in Michigan in 2010. These peas were producing nitrogen for the 2011 crop while fields that were sprayed or tilled for weed control had no such benefit.

Advantages

  1. Can provide 60-120 # nitrogen/acre (excellent if following with wheat in the fall)
  2. Can be broadcast and lightly tilled in (1″ or deeper)
  3. Can be added to other cover crops to add additional value (add to oats)
  4. Can spray with broadleaf herbicides if necessary to control weeds

Disadvantages

  1. Slower to establish than oats
  2. More costly than straight oats
  3. Seed MUST be inoculated at the time of planting

 

Crimson Clover

Advantages

  1. Can produce up to 150# N/acre within 100 days (great option if following with fall planted wheat or Winter Barley)
  2. Fairly quick to establish
  3. Relatively inexpensive
  4. Can be broadcast and lightly tilled in (1/4-1/2 inch deep)
  5. Can be added to other cover crops to add additional value (add oats at 1 bu/acre)
  6. Can spray with broadleaf herbicides if necessary to control weeds (This article is for seed production in the northwestern part of the USA)

Disadvantages

  1. More costly than straight oats
  2. Slower to establish than straight oats
  3. Seed MUST be inoculated (it may be purchased pre-inoculated)

 

Cowpea

Advantages

  1. Can produce 60-150# nitrogen/acre
  2. Can be broadcast and lightly tilled in (1″ or deeper)
  3. Can be added to other cover crops to add additional value (add to oats)
  4. Can spray with broadleaf herbicides if necessary to control weeds

Disadvantages

  1. Cost and availability of seed
  2. Slower to establish than oats
  3. Seed MUST be inoculated

Other crops to consider: Berseem Clover, Fava Beans, and others.

For further information, please read this excellent article by Barry Fisher, NRCS Agronomist from Indiana, who wrote on this very topic in 2009.

Summer Annual Grasses for Cover Crops for Prevented Planting Acres

With an abundance of prevented planting acres in Wisconsin and Minnesota in 2013, there is a need for cover crops to help build soil during the soil’s “idle” time.  In this post I’ll mainly focus on summer annual grasses that work well in the Midwest.

These recommendations will focus on whether feed is needed or not.  These cannot be harvested until  November 1 if crop insurance is taken.

If producers do not take crop insurance then there are other options mentioned below that give greater forage quality and yield.  However, many of these products are in very short supply.  Please call your local seed supplier to check on availability.

Summer Annual Cover Crops Where No Feed is Needed

I would recommend a non-BMR Sorghum Sudangrass at 10-12#/acre.  These should retail at $1.10-1.15/#.  This choice is less expensive per acre than most summer annual options.  This product is in very, very short supply for 2013.

Other cover crop options include non-BMR Sudangrass, which should be planted at a minimum of 10-20#/acre and will retail for around $1.20/#. Choices here would include Piper and Monarch V, among others.  Both of these products are in very short supply for 2013.

I would also consider Hybrid Pearl Millet. Seeding rate will be 7-10#/acre.  Hybrid Pearl Millet is in exceptionally short supply for 2013.

Plant each of these options at ½ -1” deep.  Apply at least 25-30# of nitrogen per acre so there will be some plant health.  There is very low supply on all of these items.  Farmers should mow to alleviate seed production. Mow periodically and leave 6-8” tall residual so there will be continued regrowth.

Here is BMR Hybrid Sudangrass in Late July 2009 ready for 2nd cutting.  This was seeded at 37#/acre.

Summer Annual Cover Crops Where Feed is Needed

If the prevented planting acres will be used for forage production, consider the following (with crop insurance taken–harvested after Nov. 1):

Take the options above and increase the seeding rates as shown below:

  • non-BMR Sorghum-Sudangrass  –35-50#/acre
  • non-BMR Sudangrass  — 25-30#/acre
  • Hybrid Pearl Millet –12-15#/acre

 

If the prevented planting acres will be used for forage production, consider the following (no crop insurance taken – harvested throughout the summer):

Pro Max BMR Hybrid Sudangrass.
Sudangrass can get quite tall and yield well if managed properly.

Option #1 for livestock feed I’d recommend BMR Hybrid Sudangrass at 35#/acre.  BMR Sudangrass is superior to non-BMR Sudangrass for grazing, animal production, haymaking, ensiling, etc.  Plant 35-37#/acre. Retail cost is around $1.75-1.80/#.

This is truly a superior product for dairy, beef, and sheep operations.  It is grown on many dairy and beef farms across the Midwest, Upper Midwest, and Mid-Atlantic states.  These products are in exceptionally short supply in 2013.

Option #2 is BMR Sorghum X Sudangrass.  Many BMR Sorghum X Sudangrass varieties  yield well and are very high in quality.  It is much more palatable than non-BMR products.  IF it is for dairy, plant at 50#/acre. Retail cost is around $1.45-1.50/#.  Supply is exceptionally limited in 2013.

Summer Delight Teff Grass
Teff Grass can produce great summer forage.

Option #3 is Teffgrass.  Teffgrass needs to be planted into an alfalfa-like seedbed at 1/8-1/4” deep.  Seed it at 10-12#/acre. Retail cost is $3.00-$3.25/#.  Supply is fair to good.

Option # 4 is Hybrid Pearl Millet planted at a higher seeding rate.  For forage, plant at 12-15#/acre.  Hybrid Pearl Millet is in exceptionally short supply for 2013.

See some of these products in OSU trials at:

http://oardc.osu.edu/forage2008/table15.asp and http://oardc.osu.edu/forage2009/table11.asp

Profitability for BMR  Sorghum X Sudangrass and BMR Sudangrass products is generally higher than for non-BMR products.  For instance, data on BMR Sudangrass has shown a 20% increase in animal production and therefore is considerably more profitable than non-BMR Sudangrass.  In a year like this I’d guess that maximizing profit will be important!  Be sure to use 75#/N (actual) for these products at planting time. Follow with additional nitrogen after each harvest.


This photo is taken on the same day in the same test plot as the Pro-Max seen above. Pro-Max out-yielded the Nutri-Plus by 20% in this trial in Northern Indiana in 2009.

You can e-mail me at dave@plantcovercrops.com for additional recommendations, or for locations of dealers where these products are available, or for other questions.

Mustard as a Cover Crop

This article was originally posted on December 14, 2010.

Benefits of Mustard

Mustards are a good cover crop for a variety of reasons.

One of the main benefits is that they have high levels of  glucosinolates.  According to Cornell University:

The practice of using mustard cover crops to manage soil-borne pathogens is known as biofumigation. Biofumigation is simply the suppression of various soil-borne pests and diseases through naturally occurring compounds. All brassicas such as cabbage, kale, cauliflower, brussel sprouts, broccoli, mustard, and turnips naturally produce glucosinolates, the compounds that make certain brassicas “hot”. Brassicas sold as cover crops have been identified or specifically developed to contain very high levels of these glucosinolates. The higher the levels of glucosinolates present, the better the biofumigant effect. The process works as so: when plant cells are damaged such as by chopping, glucosinolates are released and come in contact with an enzyme (myrosinase). In the presence of water, the reaction produces the natural gas isothiocyanate (ITC). ITC is responsible for the suppressive effects of the practice. ITC is similar to the active ingredient in Metham Sodium or the conventional fumigant Vapam (a.i. Methyl ITC). In addition to the soil biofumigation benefits, brassica cover crops are ideal for adding organic matter to the soil and improving many soil health related characteristics due to the large quantity of “green” or fresh biomass produced and incorporated into the system.

(http://ccesuffolk.org/managing-soil-borne-pathogens-with-mustard-cover-crop)

Take a look at the interview I did with Kim and Matt Davidson from Mighty Mustard™:

 

If you’re unable to see the video, simply refresh your browser or click on the link below to watch it on YouTube.

Advantages of mustard as a cover crop:

  • Acts as a natural biofumigant
  • Generally winterkills (at 26 degrees F)
  • Easy to kill with herbicides and tillage
  • Provides alleopathic weed control
  • Helps “clean up” problem fields where nematodes are a problem
  • Hinders the germination/survival of ryegrass and other cover crops…may be used to clean up a problem cover crop ryegrass field
  • New varieties are superior to VNS or wild mustard for nematode or weed control/suppression

Disadvantages

  • Best to be planted 1-2″ deep
  • Must be planted as a monoculture
  • Must be killed or tilled in for a minimum of three weeks before planting a subsequent cash crop
  • Must have rain or irrigation after tillage/killing to help release glucosinilates
  • Needs 5-6 weeks growth for best results
  • Must not be used for animal feed

Visit Mighty Mustard for additional information on mustard as a cover crop.

Root Pit Reveals 40″ Cereal Rye Roots

Rye Pit

I am blessed to hear from farmers around the world about their cover cropping adventures.  One young man, Brian Scott, from Carroll County, Indiana has generously shared his information with me again this spring.  This post is Brian’s report from early May, 2013.  To see Brian’s photographs, click here.

We dug a few pits in our field today that has about 40 acres of cereal rye and another 40 of annual ryegrass. The cereal rye had a pretty good stand, but the ryegrass didn’t do so well over the winter.  Looks like we may not be the only farm with that problem this year?

Anyway I was pretty excited for our first year cover cropping that we found cereal rye roots down to 40″ today!  And we hit the water table below that since everything is still relatively wet from all the rain.  I wouldn’t be surprised to see more roots if we could have dug down deeper.  That was on pretty good soil that used to have manure applied every year until about 7 years ago when we got out of the hog business.

The ryegrass was on ground with much more clay near the surface, but I was glad to see we had roots down 2 feet where we did get a decent stand.

Both covers were sprayed today.  I think I would have liked to keep the cereal rye a bit longer, but with rain in the forecast we didn’t want it getting out of control if we got soaked again and couldn’t spray.  These were all seeded into standing corn on 9/19/2012.  In all we had about 200 acres of cover this year and have plans to seed at least 400 in the fall!

Thanks Brian!  And to everyone who have been sending info…watch for it to be on the blog soon.  Thanks to all who are sharing their stories.

Cover Crops: Buy One Year, Get Another Year Free

Surprise! That's what our reaction was to the volunteer annual ryegrass growing in our fields nearly 18 months after they were sown.
Surprise! That’s what our reaction was to the volunteer annual ryegrass growing in our fields nearly 18 months after they were sown.

Almost two years to the day I posted an article about Killing Tall Annual Ryegrass.

The problem of a wet and chilly 2011 has resurfaced an ugly head to be a wet and COLD spring of 2013. But over the past week or so temperatures have warmed into the 70’s and 80’s with cover crop annual ryegrass and winter cereal rye having grown tall in some areas of the Midwest. Producers need to kill their cover crops as soon as possible to comply with RMA regulations.

What about the surprise cover crops?

In a previous post I wrote about dormant seed in cover crop species on our home farm.

I showed how radishes were present in soybean fields and how annual ryegrass was coming up even after there was residual herbicide and burndown herbicide applied.

Now here we are in the spring and we have a few new surprises.  Fall 2011 planted annual ryegrass and even fall planted winter cereal rye are now growing in the spring of 2013.  These cover crops were fully terminated in the spring and summer of 2012; there was effective weed control.  So dormant seed has germinated and now grown a full 15-18 months after it was seeded.  So yes, cover crops can become weeds.

(But remember, cover crops also suppress weeds.)

So what does this matter?

We have the benefit of a “thin” cover crop and we did not have to pay seed cost or application cost for the second year.  In our farming situation it is not a big deal.  We terminated all of our cover crops and weeds with a “hot” chemical mix.  It is a mix similar to what we used in our no-till fields prior to glyphosate coming on the market.  However, if we were growing wheat or oats or barley for grain and straw it could be a problem.  Thankfully there are now chemicals to use in cereal crops to eliminate annual ryegrass.  I hear reports that Jamie Scott from northern Indiana has seen excellent results with this practice.

We have less winter annual weeds where we have the “volunteer” cover crops and I’m confident our soil health is better where we have the cover crops.

What do we do now?

We enjoy the benefit that we have from the cover crop (even though it is a sparse stand) and we watch to make sure we do not have any cover crops coming back before harvest. The cover crops are now dead and a residual herbicide is applied.  Now we wait to plant the corn and soybeans and scout for any additional dormant seed to germinate and grow.  A clean harvest is important to all producers.  Our goal is to use the information from our own farm to make sure that farmers understand the rewards that cover crops bring and also the risk that comes with the reward.  The risk is not huge and it is manageable, but it is risk none-the-less.

 

This volunteer annual ryegrass was terminated before heading out but it was jointed and would have made a great forage plant.
This volunteer annual ryegrass was terminated before heading out but it was jointed and would have made a great forage crop.

 

 

 

 

 

 

 

 

Volunteer Winter Cereal Rye was also growing in the old plot area. The cover crop was terminated well before the corn will be planted.
Volunteer Winter Cereal Rye was also growing in the old plot area. The cover crop was terminated well before the corn will be planted.

 

Do Cover Crops Keep the Soil Colder in the Spring?

Fact or Fiction? Cover Crops that Survive the Winter Keep the Soil Colder in the Spring than Fall-Tilled Soil

This is a question I get over and over again.  And most of the time it’s not really a question. It’s actually someone stating to me why they are not going to plant cover crops. But is it really true that a surviving cover crop will keep my soil colder than a conventionally tilled soil?

Several years ago in March I stopped at a cover crop test plot on the Indiana/Ohio border.  While I was there I checked the soil temperature where cover crops had survived (Annual Ryegrass and Winter Cereal Rye) to see if it was indeed colder than the tilled soil that surrounded the plot.

Surprising Results

What I found was a bit surprising considering the conventional “widsom” I commonly heard.  The soil temperature at 4″ depth was warmer by 1-2 degrees where we had a surviving cover crop than in moldboard plowed dark soil.  I sampled on a sunny day when the temperatures were in the 40’s.

Since then I have taken comparative soil temperatures in many locations where no-till was done, where there was no-till with cover crops, and where there was fall tilled soil.  In nearly every instance the area where there was a cover crop the soil temperatures were equal to or above the fall tilled soil temperatures.  Each of these samples were just taken one time – a snapshot test in time.

More Testing

This spring my brother Don Robison is taking soil temperatures and photos of a soil thermometer from our home farm near Greenwood, IN. He started taking these photos on March 29, 2013.  The plan is that Don will take soil temperatures for four or five consecutive Fridays – in annual ryegrass, in no-till soil (that has some winter annuals present), and in fall tilled soil.  And since March of 2013 has been quite cold when compared to recent years, the results should be interesting.

Results Will Be Recorded

Each week I will post the temperatures as Don send them to me.  Below you can see the temperatures from March 29.  Be sure to check back weekly for the results.

Do Your Own Experiment

Send me temperature readings and photos (phone camera quality is fine) and I’ll compile some data from different parts of the country (world) and pass the data along.  Please let me know your soil types and general weather conditions when you send in your reports.

The soil temperature on March 29, 2013 at approximately 4 inches in fall tilled soil.
The soil temperature on March 29, 2013 at approximately 4 inches in fall tilled soil.
The soil temperature on March 29, 2013 at approximately 4 inches in an annual ryegrass cover crop.
The soil temperature on March 29, 2013 at approximately 4 inches in an annual ryegrass cover crop.
Soil temperature reading on March 29, 2013 in no-till soil.
The soil temperature reading on March 29, 2013 at approximately 4 inches in no-till soil.

Kura Clover – The Perennial Cover Crop

Kura Clover is an interesting option for cover cropping no-till corn producers. Why? Because Kura Clover forms a “living mulch.”

I have been working with Dr. Ken Albrecht from the University of Wisconsin-Madison on Kura Clover since the summer of 2000.  During that summer as I traveled through eastern Iowa and NW Illinois I envisioned that before 2005 all of that region would have Kura Clover on it!

That never happened. But I am still very excited about Kura Clover as a feed source and cover crop.

For Kura Clover to be best utilized on your farm you really need to graze it the first two years and periodically thereafter. Cattle milked similarly on this mixture as what they did on alfalfa!
For Kura Clover to be best utilized on your farm you really need to graze it the first two years and periodically thereafter. Cattle milked similarly on this mixture as what they did on eating alfalfa haylage!

What’s so great about Kura clover?

Kura clover:

  • Produces high yields with little additional nitrogen
  • Fixes gobs of nitrogen
  • Forms a “living mulch”
  • Survives forever – stands last 30+ years
  • Makes livestock producers/row crop farmers smile
  • Provides diverse options in the field
  • Saves cover croppers money – a one time investment in seed
  • Controls erosion 
  • Is easy to work with in corn production

Why hasn’t Kura clover taken over the cover crop/forage world?

  • It establishes slowly.
  • It requires livestock (cattle or sheep) to be a part of the program for optimal benefit.
  • You cannot plant corn into Kura Clover every year.
  • You cannot plant soybeans into Kura Clover.
  • It must be inoculated with a special inoculant for it to establish/thrive.
  • It costs a lot in establishment year.
  • There are few producers of Kura clover seed – the biggest is CISCO Seeds.
This Kura Clover was ready to be sprayed with the second application of glyphosate to burn it back so the corn could take off. This plot yielded over 185 bu/ac the year this photo was taken.
This Kura Clover was ready to be sprayed with the second application of glyphosate to burn it back so the corn could take off. This plot yielded over 185 bu/ac the year this photo was taken.

 

Corn growing in Kura Clover in Arlington, Wisconsin.
Corn growing in Kura Clover in Arlington, Wisconsin.
Note that this photo (taken in October 2002) shows large ears and a beautiful crop of Kura Clover growing under the canopy.
This photo (taken in October 2002) shows large ears and a beautiful crop of Kura Clover growing under the canopy.

 

 

 

 

Cover Crops in Noble County, Indiana

State and local Soil and Water Conservation Districts have been a wonderful partner over the past 4 years in helping to educate farmers about the value of cover crops in their local area.  Over the past four years Indiana SWCDs have planted or overseen over 300 cover crop test plots.  Recently the Noble County (Indiana) Soil and Water Conservation District held a field day where they did a great job of educating area farmers on the benefits and applications of cover crops for their county.

First, they put together a cover crop information sheet showing the various seeds and mixes that can be planted, as well as the seeding dates for their area.

Second, they provide a list of local suppliers for seed, herbicides, and applicators.

But most impressive is the test plot they put out. Working with a local farmer, they seeded 9 different plots, along with a “check” plot, which had no cover. They purchased the seed from Ag Plus, which is located in Columbia City, IN.

Below are pictures from the plot, which were taken on October 11, 2012. The plot was seeded at 3/4 inch using a drill – on August 24. Stacey McGinnis, from Noble County SWCD noted that quite a lot of volunteer wheat came back up and the ground was fairly compacted (soil is a silty clay loam). On Monday, October 8, there was a killing frost.

When asked what the goal of the test plots were, Stacey commented “to get farmers who are on the fence about cover crops to begin to experiment” and “to get farmers who are using some cover crops to begin to try some of the mixes, which will give them more benefit.”

Below are the pictures from the plot, along with a brief explanation of some of the benefits below each picture. You can click on the picture to see a larger version. Also, hover your mouse over the picture for a quick description.

Winter Rye

Winter Rye:

  • can be established later than many other cover crops
  • will overwinter
  • works extremely well when the next crop is soybeans

Winter Rye & Radish Mix

With winter rye and radish mixed together, you get:

  • all the advantages listed above for winter rye, plus the radish will:
  • scavenge left-over nutrients
  • break up compaction
  • invite quite a few earthworms to the party

Austrian Winter Peas & Radish Mix

Along with the advantages of the radish, Austrian winter peas produce nitrogen for the next crop. So, by mixing these two together, you have a nitrogen producing and nitrogen scavenging environment all mixed into one.

Oats

Oats are great for several reasons. Oats:

  • scavenge nitrogen from the soil.
  • have a deep and fibrous root mass.
  • are excellent for forage.
  • winter kill very easily.
  • work very well with other cover crops in mixes.

Oats & Winter Rye & Turnips

This mixture of oats, winter rye, and turnips has several advantages for livestock producers. The oats produce a tremendous amount of forage for the fall, while the winter rye will over-winter and give you more forage for the spring. The turnips adds a lot of protein for the livestock, but are also very capable nitrogen scavengers themselves.

Buckwheat

 

Buckwheat is a useful green manure crop. It can produce significant amounts of dry matter. Up to 3 tons of dry matter per acre has been obtained after 6 to 8 weeks of growth on relatively unproductive land under Pennsylvania conditions. When plowed under, the plant material decays rapidly, making nitrogen and mineral constituents available for the succeeding crop. The resulting humus improves physical condition and moisture-holding capacity of soil. Where a second crop of green manure is desired, rye may be drilled into the buckwheat stubble and plowed under in the spring. The rye frequently can be drilled into the buckwheat stubble without previous disking or plowing. Buckwheat green manure may also fit into fairly tight rotations such as when a crop is harvested prior to mid-July and a succeeding crop is not scheduled until fall. If volunteer buckwheat is harmful in the succeeding crop, then the green manure crop of buckwheat should be destroyed before a large number of seeds mature.

http://www.hort.purdue.edu/newcrop/afcm/buckwheat.html

As noted above, there was a killing frost on this plot on Monday, October 8. However, that is not what killed this buckwheat. This buckwheat plot was killed 3 weeks prior with a light frost. Notice also that the oats and radishes look just fine, even after the first killing frost.

Annual Ryegrass

Annual ryegrass is:

  • deep rooted and helps mine minerals from deep in the soil profile.
  • an excellent erosion control crop.
  • a luxury consumer of nitrogen and tremendous scavenger of N.
  • easily aerial applied into corn and soybeans.
  • an excellent forage crop.

Annual Ryegrass & Crimson Clover & Radish

This is a cover crop mix on steroids. Two excellent compaction breakers are mixed with the nitrogen production of the crimson clover.

No Cover Crop

As you can see, where there is no cover crop, weeds are starting to take root.

Thanks to Stacey McGinnis at the Noble County SWCD for this excellent cover crop work. Thanks to Mark Perry from Beck’s Hybrids for sending these pictures to me and keeping me up to speed on the cover crop work going on in Noble County. And thanks to Jim Eiler from Ag Plus in Columbia City for hustling some last minute seed over to this site so they could get everything planted at the same time.

If you’ve not had a chance to get out to a cover crop field day or a cover crop test plot, and there is one in your area, try to schedule a time to take a look. Let the experimenting begin.

Cover Crop Turnips – A Good Choice Over Radishes?

Cover Crop Radishes or Turnips as a Cover Crop – or Both?

Cover crop radishes certainly receive a lot of press. I have researched them quite a bit over the past four years. On this blog alone I have over 20 posts about radishes. They are fun to take photos of, dig around in, research, and even play baseball with.

It is hard to pick up a publication that mentions cover crops and not read about radishes and their benefits.  Some industry and university cover crop research leaders like Steve Groff and Dr. Ray Wiel (University of Maryland) have researched radishes for over 10 years.You might say that cover crop radishes are the “Rock Star” of cover crop species these days.

What About Turnips?

The Oats are nearly 30" tall and the turnips are around 18" in this Oactober photo. The Cereal Rye was about 6" tall at this time. This mixture was planted in late August and the photo was taken Oct 22 - approximately 8 weeks after planting. My daughter Grace was the model..
The Oats are nearly 30″ tall and the turnips are around 18″ in this Oactober photo. The Cereal Rye was about 6″ tall at this time. This mixture was planted in late August and the photo was taken Oct 22 – approximately 8 weeks after planting. My daughter Grace was the model..

Why are turnips used as a cover crop so little compared to radishes? Are they the “ugly step-sister” of the Brassica family?

Let’s look at some of the benefits of turnips. Some newer varieties (Appin in particular) provide a bulb that is almost entirely in the soil and a deep root system (though a smaller bulb/tuber than the radish).

Benefits of Turnips

  • Turnips are very palatable for grazing cattle and sheep.
  • Most turnips survive the winter and hold onto nutrients into the spring (longer than radishes).
  • Turnips sequester nutrients in a similar fashion and amount as radishes (see data below).
  • Turnips are easy to kill in the spring.
  • Turnips do not have the odor problems that radishes have (therefore they can be planted more “safely” in areas closer to towns or neighbors).

“Problems” with Turnips

  • Not all turnips are created equal. The old purple top (or that type) turnip and even the tankard type turnips have very little of the bulb in the soil – thus less soil activity.
  • Most turnips survive the winter and then need to be killed in the spring. Yes this can also be a benefit.
  • The turnips “bolt” in the spring and want to produce seed. Kill them as early as possible.

    Turnips will overwinter in the spring. The turnips above flowered out in March 2012 in central Indiana. This is nearly 5 weeks before “normal”

Frequently Asked Questions

  1. If we mix turnips and radishes together, is that okay?  YES – for grazing or for just using as a cover crop.
  2. If we plant turnips instead of radishes is that okay?  Yes – just be aware of the differences and that the turnips will most likely survive the winter.
  3. What if we are just looking to graze and only care some about the cover crop?  Choose turnips.
These three brassica types were collected from a Loundonville, OH farm in the fall. Pasja Hybrid Brassica (L); GroundHog Cover Crop Radish (C); and Appin Turnip (R). Note the difference in tops versus tubers.

 

Nitrogen tested in Radishes/acre from Loudonville, OH dairy farm  averages 200 units of N (data collected November 2010)

Nitrogen tested in Appin Turnip/acre from Loudonville, OH dairy farm showed nearly 300 units of N (data collected November 2010)

The turnip tops had nearly 200 units of N/acre.  This was NOT scientific but it is instructive that turnips are an excellent scavenger of N.

Grazing Cover Crops

These cattle have a great body score as they graze on December 6, 2011 in northern Indiana.

In early December, 2011 I visited two farms in Kosciusko County Indiana (NE IN) where producers had intentionally planted cover crops after their wheat was harvested for the purpose of grazing cattle and improving soil.  One of the producers planted a mixture that was featured in this blog.  His Oats/Cereal Rye/Turnip mixture looked beautiful and it appears he will have more feed than he needs to get the cattle through December without feeding much hay!  Only a severe ice storm or exceptionally wet soil would seem to prevent that from happening.  Here is a video my wife and I took from this field.

Just down the road a different farmer planted a different mixture.  His pastures were decimated by the summer drought and over grazing.  Frankly I would not have recommended the mixture he planted…only because I was not sure how the cattle would graze cover crop radishes.  His mixture was 3# Appin turnips and 3# of GroundHog cover crop radishes.  That was all…When my new farmer friend drove me by the field I did not see the cattle…and even then I was noticing a lot of bare soil (the area between all of the brassicas) and was longing to see oats or some grass species out in the field with the brassicas.  Then we found the gent that planted the field.  He was ecstatic!  The cattle were grazing both the turnips and radishes very well. His cattle had great body condition and his feed bill was way down.  My only recommendation was that he feed dry hay to the cattle along with the brassicas so that they would not end up with some health issues (acidosis, foundering, etc…).  Brassicas should not make up more than 30-35% of the diet for cattle and he was at over 80%.  Watch a video from this field.

Here is my wife in the field of cover crop radishes and Appin Turnips on Dec 6, 2011. Note the uncovered soil...that is just another reason to add oats and or cereal rye or annual ryegrass to this mixture.

 

The cattle needed more fiber in their diet so they ate a significant amount of turnip bulbs. They ate far fewer radish tubers than turnip tubers.

 It is very important to include fiber in the diet of the cattle when grazing turnips and radishes.  The forage quality of the brassica is too high for the cattle to have a healthy rumen. If the producer that planted only the brassicas had fed straw or lower quality dry grass hay the cattle would have been healthier.  I believe that is why the cattle were eating so many bulbs…they needed more fiber.

This line of straw bales were used for bedding in the barns instead of feed for the cattle in the brassica field.