Plant Cover Crops

Learning about the benefits of planting cover crops.

Crimson Clover

Cover Crops to the Rescue!

A Huge Problem

Brad, TJ, and Andrew inspecting on of Brads many cover crop fields that were planted in July 2013.on prevented planting acres.
Brad, TJ, and Andrew inspecting one of Brads many cover crop fields that were planted in July 2013 on prevented planting acres.

Recently I was in Minnesota with Brad Hagen, T.J. Kartes, and Andrew Heath looking at Brad’s 1,000+ acres or cover crops.  Brad had not intended on planting any of theses acres to cover crops in July, 2013…his intentions were to plant them in August or early September.  But spring 2013 rains and floods kept Brad from planting corn or soybeans on most of his 1,700 acres near Ellendale, MN (about an hour SW of Rochester, MN ).  Brad attended a cover crop meeting TJ set up for me to speak at on behalf of Legacy Seeds last March and as I spoke I could see Brad’s mind working.  When the spring rains came so did phone calls from Brad to TJ and from TJ to Andrew or me (or both)…”what can I do to build soil during this disaster?” was the theme of the weekly (if not daily) phone conversations.

You can seemingly look for miles without seeing a cash crop planted in some areas of SE Minnesota
You can seemingly look for miles without seeing a cash crop planted in some areas of SE Minnesota

Cover Crops to the Rescue!

Brad’s goals are to build soil and to scavenge nitrogen from his hog operation and build nitrogen with legumes.  Realizing that we would plant in early-mid July and not in mid-late August we all understood that we did not want to have to mow to remove seed heads if at all possible – so we left Radishes out of the mix.  We also realized that we wanted to use a “summer” clover, so we used Berseem Clover for it’s excellent growth and N producing ability.  We chose Oats as the grass in most fields and then we added a twist, Pasja or Vivant Hybrid Brassica.  I have worked with Pasja for over 10 years and rarely ever saw it produce a seed head in the summer or fall.  While Pasja (nor Vivant) have a big tuber like a Radish they do have the ability to scavenge a tremendous amount of nitrogen and earthworms dwell around their roots.

Brad Hagen looking at his Pasja Hybrid Brassica and Berseem clover. These are brand new species to Brad.
Brad Hagen looking at his Pasja Hybrid Brassica and Berseem clover. These are brand new species to Brad.  This field was planted 10 days before the photo was taken.

In some later July (and soon to be mid-August) planted fields we chose to use Spring Barley and Crimson Clover along with PileDriver Radishes and Appin Turnips.  TJ and Brad requested this mix so we’d get later fall growth, deeper penetration through compacted soils (Radish vs. Pasja/Vivant) and excellent N production from the Crimson clover.  Spring Barley was available and many folks in Kentucky have told me that barley makes the soil “sweet” (whatever that means).  From experience I know that soil after Barley is quite mellow.

Early August Report

From what I saw on August 1 I was very impressed!  As other folks in the region were planting straight Oats or possibly a few were adding Radishes very few other folks seemed to totally share Brad’s goals.  Brad told me that he is doing these cover crops because he wants to build his soil and because he wants his 7 year old son to have better soil to farm when he grows up and farms his place like Brad does with his father.  I’ll have more photos in a month or so.  I believe Andrew, Brad and TJ will plan a field day for September.  It’s beautiful country near the Hagen farm…it probably will be worth the drive in September to meet Brad and his family.  They’re pretty special folks…

Take a look at my You Tube channel “covercropdave” to watch an interview I have with Brad and TJ.

This beautiful stand of cover crops was planted July 2, 2013 at Brad's dad's place not far from the hog barns. If you sniff this photo real hard you can smell the hogs!
This beautiful stand of cover crops was planted July 2, 2013 at Brad’s dad’s place not far from the hog barns. If you sniff this photo real hard you can smell the hogs!

 

 

 

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.

Fertilizing Cover Crops & Planting Legumes After Soybeans

If you spend any time at all in cover crop meetings, you may have heard that it’s a good idea to add 20-50# of Nitrogen per acre to your cover crop – if you don’t have a legume in the mix or you don’t have manure available. You also probably heard (or participated in) the grumbling that predictably starts from the crowd. Who wants to fertilize a crop that they will not harvest?

While it’s true that producers will not “harvest” the cover crops, they will have healthier cover crops which should lead to healthier soils and healthier profits.

Manure as the No-Brainer

Obviously if manure is available it is a smart move to put manure where you will have or already have cover crops.  We know from research that cover crops can hold as much as 90% of the nutrients from manure applications.

We have also know that where manure is applied without a cover crop being present (even if worked in) we can lose a significant amount of nutrients into ground water or as surface run-off.

What About Adding Commercial Fertilizer?

The Radishes on the left had manure applied and those on the right did not have any additional nitrogen applied.
The Radishes on the left had manure applied and those on the right did not have any additional nitrogen applied.

But, what if there is no manure to apply and for some reason you do not want to include a legume in your system?

Is it worth applying 50# of nitrogen to produce a cover crop?

Let’s look at what we think we know:

  • Pages 22-24 of Managing Cover Crops Profitably provide formulas to figure out the value of using cover crops as a green manure in a cover crop system –  whether with legumes, manure, or fertilized.

Look especially at the section on “Potential losses” to see that there can be nitrogen losses even in this scenario.

  • Cover crop experts say to count on 50% of the N captured or N produced by a cover crop to be available to the next cash crop.
  • It appears that adding a grass with legumes or brassicas will help “slow down” the release of the N in the spring making it more slowly released to the next crop.

 

Here is a photo of the Ingham County Michigan Cover Crop Plot. Where there was a legume in the mixture there was considerably more growth and earthworm activity
Here is a photo of the Ingham County Michigan Cover Crop Plot. Where there was a legume in the mixture there was considerably more growth and earthworm activity

What can we expect if we plant a cover crop and we don’t add more nitrogen?

How will that cover crop do?

I will utilize work that Dan Hudson did when he was an Extension educator in Ingham County Michigan in cover crop plots he planted back three or four years ago.

  • Radish tubers are considerably smaller and the roots appear to not be as deep  (I have not dug a root pit in this scenario).
  • Grasses have a more shallow root system in forage settings when fertility is lacking.
  • The cover crops were pale green.
  • The “hungry” grass cover crops had less earthworm activity than in the grass + legume mix plots.
  • “Hungry” radishes and turnips had much less tuber and top growth, thus sequestering less nutrients (one of their main functions).
  • Winterhardiness on cover crops is potentially not as good when the cover crop is undernourished.

What can we expect after soybeans?

Do we need a legume in the cover crop mix following the beans or is having a grass and/or brassica to sequester the N from the soybeans good enough?

Let’s investigate the difference between adding a legume to a cover crop mix following soybeans compared to planting scavengers only.  The charts are from our family farm trials.  The charts show the chlorophyll readings of the corn in the year following the soybeans (and then following a cover crop).

It is important to look at the “Y” axis as each chart is slightly different in how it shows the top reading.

When Austrian Winter Peas were added to a scavenger (Radishes) the chlorophyll readings were very favorable compared to the no cover crop check plot and plots with just scavengers.
When Austrian Winter Peas were added to a scavenger (Radishes) the chlorophyll readings were very favorable compared to the no cover crop check plot and plots with just scavengers.
Just like the peas gave us an advantage over the no cover crop check the crimson clover showed very favorably.
Just like the peas gave us an advantage over the no cover crop check  and scavengers, the crimson clover also showed very favorably.

 

While the Oats and Radish showed exceptionally favorable in the early part of the season the plot are "ran out of gas" as the corn was pollinating.
While the Oats and Radish showed exceptionally favorable in the early part of the season the plot “ran out of gas” as the season progressed.
Straight Winter Cereal Rye was impressive early season but also did not fare as well against the check as the mixes with legumes
Straight Winter Cereal Rye was impressive early season but also did not fare as well against the check as the mixes with legumes.

As we looked at the yield of the corn in these plots we saw a considerable difference – suggesting that even after soybeans we might want to add a legume to improve the corn yield the following year.

Yields from the different cover crop plots shown above were:

Check Plot                                    105.24 bu/ac

Winter Cereal Rye                      126.86 bu/ac

Oats and Radish                          138.79 bu/ac

Crimson Clover + Radish           153.99 bu/ac

AW Peas + Radish                        164.82 bu/ac

Conclusion

All indicators seem to point that adding manure, a legume, or additional N might very well pay off when planting a cover crop, even after soybeans.  However, adding a nitrogen source is not necessarily vital to having a successful cover crop system.  I would suggest that you try different scenarios on your own farm and in your own system and see what works best for you.

Is it Ever Too Early to Plant Cover Crops?

Is it ever too early plant cover crops?  YES.

As many of you have figured out, I sell seed for a living.  I also have been a farmer or involved on the farm since I was a little boy.

But first and foremost I am an agronomist.

The temptation of a seed salesman is to recommend planting a cover crop either too early or too late – and then somehow justify it. However, as an agronomist and a former farmer, I simply cannot do that. I also want to be able to look at myself in the mirror without guilt.

Cover crops have to work for the farmer, not the seed salesman.  There are several fantastic seedsmen out there and I do not want to disparage that fine profession.  I feed my family by being a seedsman and marketing seed. Most seedsmen are a trusted source of information and quality seed.

Questions I Get A Lot

The planting date question comes up a lot. For example:

  • How soon can a farmer plant cover crops after wheat has been harvested?
  • Can a farmer plant clovers into corn at “the last cultivation?” (even though only a few farmers still cultivate).
  • When is it too early to plant radishes?
  • When is it too late to plant radishes?

Money has not always been good in agriculture and I doubt that this current boom will last forever (it never did before).  So I want to give answers based on sound agronomic practices that will work 90% of the time.

Question: Can you plant crimson clover at “lay-by”?

Yes you can.  My granddad did that practice back in the 1950’s.  Of course he planted in 38″ rows with 16-18,000 plants per acre.  He did not use herbicides but he did cultivate.

However, how many of us farm like my granddad did?  A few of you might –  with good reason to do so (specialty corn or organic production).  But, can it work with modern herbicides and plant populations pushing 35,000 plants per acre?  Maybe, but not consistently – and probably not.

I think I tried to say “no” but I’m aware that some farmers have done it.  But, can we do a practice if it is not going to work 90+% of the time?  Not on a large scale.  Can we afford to try it on a few acres?  Maybe.

Here is a northeast Indiana farmer’s testimony of his success spreading crimson clover into his growing corn at sidedress time.  I am sharing this exactly as it was sent to me – trusting that it is accurate. I do not know the farmer who submitted the testimony.

I broadcast 10 lbs/acre of crimson clover at sidedress time this year. I seeded it on 6/6. We got essentially no rain from the first week of May until the last week of July. I figured the clover wouldn’t grow, but it laid there until we got rain and by harvest we had a nice stand. I’m not sure how this would work in a ‘normal’ year, but it sure worked good this year. I left some check strips and the clover didn’t affect the yield.   The seeder was just an old 12V spinner seeder I clamped onto our N toolbar. I’m attaching pictures of it and the clover stand. 

Photos provided are below.

My Observations

My guess is that this farmer used only glyphosate and no residual herbicide.  It was also terribly dry this summer and this seeding would have been more like a “dormant seeding”.

This was not at all typical for an Indiana summer. It was the driest July on record and June and August were also very dry.  Note how short the corn is in the photo with the corn head.  There was a lot of corn 3-5′ tall this year in Indiana.  I’d guess that a 5 foot height would cover the corn height in this field.  If the crimson would have been planted in a “normal” year I would be surprised if he would have had success like this.  But, boy, it sure is a beautiful stand in these photos!

If you try this practice, just experiment with a few acres to see what works on your farm.

Seeding Crimson Clover at “lay-by” in June in NW Indiana.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note how short the corn is in the photo. Contrary to the belief of Illinois and Iowa farmers, this is not typical for NW Indiana corn! Most likely the rains that came in August were adequate to germinate the clover and there was plenty of sunlight getting to the ground so the seedlings had heat, moisture, and sunlight. What a beautiful cover crop!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Here is a beautiful stand of crimson clover between rows of harvested corn! Unfortunately the lack of corn fodder shows that the corn was under severe stress in 2012. While achieving a nice cover crop is important, I would prefer 200+ bushels/acre corn and a less advanced stand of clover at harvest time.

Question: Can you plant radishes right after wheat harvest?

No.

Even if you use an excellent radish,  it will bolt.  I don’t care which radish you use – it WILL BOLT if you plant it too early in the summer.

Bolting means that it will try to produce seed.  Generally a radish that bolts has a smaller and shorter tuber and most of the plant energy goes to seed production instead of root tuber production. If you wait until early August and use the proper radish you will see very little if any bolting.

I have been in several fields this fall that had no plants bolted.  I have also seen many fields that had a high percentage of plants that bolted.  Some claim that the exceptionally high soil temperatures in the summer of 2012 caused the August planted radishes to bolt.  That may be the case.  One thing I know for certain, if a radish is planted in July, it almost always bolts and can produce viable seed in the fall – and that could create potential problem for years to come.

Dave’s Best Advice

Wait until August to plant your cover crop radishes.  Use the few weeks between wheat harvest and planting cover crops to clean up weeds that were in the wheat field and also control volunteer wheat.  Patience is a great virtue.  It is important that you see an excellent return on your investments that we make in cover crop seed and seeding cost.  Our goal should not be “to be done first” but rather to have the best cover crop and healthiest soil.

I hate seeing fields like this as I know there was potential for seed to be produced and dropped to the soil possibly creating some issues in future years. Was this field planted too early or was the wrong radish planted? I do not know but I do know that farmers should chose wisely on planting time and what radish to plant.  Thankfully not every plant bolted so there are still plenty of plants “doing the radish thing” in the soil very well.

Inoculating Cover Crop Legumes Pays Off

Several farmers have asked me why they need to spend an “extra” 4-6 cents per pound to inoculate the legume seed they are planting for producing nitrogen with their cover crops.  I get asked this especially about Austrian Winter Peas and Cowpea.

However, if you are planting Crimson Clover, Berseem Clover, Kura Clover, Alsike, Hairy Vetch, Sunn Hemp, or Medium Red Clover it’s just as important inoculate!  Why?  I’ll list a few reasons below:Inoculated peas are significantly better at producing nitrogen

  • Legumes are planted as cover crops most specifically to produce nitrogen.
  • Legume seed is relatively expensive; if it does NOT produce nitrogen, then it is exceptionally expensive.
  • The inoculant is a species specific bacteria that allows that plant to fix nitrogen.  If there are not enough bacteria there is limited nitrogen production from the legume plants.
  • A healthy legume cover crop can produce nearly 200 units of nitrogen
  • Even if you have produced a similar crop in your field within a two year time period, it still pays to inoculate each year since many of the bacteria prove to be “weak” and unable to perform like a healthy and vigorous bacteria.
  • If inoculating Peas or Cowpea you will need to do a “seedbox” treatment.  There are not yet inoculants that can be pre-applied that will allow you to have healthy bacteria. Therefore, most inoculant companies suggest putting the inoculant on within hours of putting the seed in the ground.

Be sure to get very good coverage on all of the seeds.

Do not hurry. Each seed needs coverage to actually be inoculated. I know that sounds silly, but I have seen many fields and plots where only some of the pea or vetch  plants were performing well.  The ones that looked poor had no nodules.

Many companies sell pre-inoculated clover seed.  If yours does not, then either find another supplier or purchase the correct inoculant from your current seed supplier.  Do not waste a great opportunity to produce as much nitrogen as possible. It is  less expensive to produce nitrogen than it is to purchase it.

A well inoculate Austrian Winter Pea nodule will be pink inside like the one above.
This photo shows a mixture of well inoculated and poorly inoculated Austrian Winter Pea plants. It is important to inoculate each seed with the nitrogen fixing bacteria.