Plant Cover Crops

Learning about the benefits of planting cover crops.

timing of planting cover crops

Cover Cropping North of I-80 After Corn & Soybeans – A Whole New World?

There is a lot of Iowa and Minnesota and Wisconsin above I-80. Is this all part of the “no cover crops works here after corn and soybeans” zone? Maybe not!

Sarah Carlson from Practical Farmers of Iowa reminded me that cover cropping north of I-80 is different than cover cropping in northern Indiana.  She’s right.  But how different is it, and why is it different?

Sarah is quoted in a very good article in Corn and Soybean Digest that helps explain the differences.

Several farmers in Wisconsin and northern Illinois are having cover crops aerial applied with good success. But I agree with Sarah; there are still challenges.

Cover Crop Challenges in the North

This field of Annual Ryegrass is in SE Wisconsin and was aerial applied into standing corn in the fall of 2011 with great success.

I see the following challenges to using cover crops North of I-80 after corn and soybeans:

  • Shorter growing season after corn and soybean harvest
  • The use of “full season” (for the region) soybean varieties and corn hybrids to maximize yield potential
  • Fear using winter cereal rye (their best option after corn and beans) because of potential risks
  • Fewer choices for cover crop species to use
  • Harsh winters and less snowfall to protect smaller cover crop plants

Cover Crop Opportunities in the North

  • More aerial applicators successfully flying on cover crops into standing corn and soybeans
  • Improved yields following winter cereal rye, a crop that can be planted late
  • High yields and profit with shorter season corn allowing timely application of cover crops
  • Annual Ryegrass is working well in southern Wisconsin and southern Michigan and there are many positive results from using it.
  • Dixie Crimson Clover has a good history of surviving the winter even in mid-Michigan and southern Wisconsin.
  • Late planted Austrian Winter Peas are overwintering as far north as the top of the Thumb of Michigan.
  • Winter Barley (winter hardy varieties) is surviving well in southern to mid-Wisconsin and in southern Minnesota and used for a cover crop or haylage before planting corn silage.

While not every producer North of I-80 will have success with cover crops after corn and soybeans, there are a number now that are happy with their results.

My message is to use wisdom and best management practices.

IF you want to try cover crops after corn and soybeans and you are north of I-80, realize that you are not the first person to try it.  Many have gone before you with good results.

Don’t give up before you investigate the possibilities.

Now, if you are north of I-90…

Short Cover Crops Put Down Deep Roots

Many cover crops were planted in September and even into early October in much of the Midwest in 2011.  Some of those cover crops are not very advanced in their growth by mid-November. Does this mean that they are useless or worthless?  As I often say in meetings or at field days…”always take a shovel with you.”  You will likely be surprised!

I have been in several root pits this fall and also have dug up dozens of cover crop plants.  One of my goals in the field is to measure roots on species like annual ryegrass, cover crop radishes, oats, cereal rye, Austrian winter peas, rape, kale, cowpwea, Hairy Vetch, Phacelia, turnips, and crimson clover.  Some of the cover crops were in fields that were long term no-till and some were conventionally tilled.

So what have I found so far?

  • Four inch tall Annual Ryegrass with 21″ deep roots

    Very little top growth does not mean very little root growth. This radish had well over 12" of root depth.
  • 15″ deep radish roots that had 2″ tall tops and a “pencil” sized tuber
  • 12″ deep crimson clover roots under a 2″ tall top (with many nodules)
  • 35″ deep roots on oats that had 20-25″ tall top growth (prevented planting situation planted in early September)
  • 30″ deep roots on radishes that had 20-25″ tall top growth and 2-3″ diameter tubers (prevented planting situation planted in early September)
  • 12″ deep roots under 18″ tall Austrian Winter Peas (planted in late August after wheat)
  • 20″ deep cereal rye roots with 6″ tall top growth (planted in late August after wheat)

While it would be nice to have more top growth, what’s below the soil surface is impressive.  As I learned from Dr. Eileen Kladivko from Purdue University nearly 8 years ago…it’s what is below the surface that really counts for most farmers.

Earthworms were abundant in the cover crop soils, but not so much in the non-cover cropped fields.  Another factor that was impressive was the amount of roots…or the density of the root mass in the soil, even on the short cover crops.

So why does this matter?  If we are to have better soil structure we need living roots.  If we are to have better erosion control we need living roots.  If we are to scavenge nutrients, we need scavenging roots.  In fact, the roots are what gives us the vast majority of the positive benefits most producers find with their cover crops.  Cover crops farmers can’t be “windshield” farmers…they need to have their shovel with them…and when they see the roots, that’s when cover crops get the most exciting to them…and me.

 

It's hard to believe it but this short crimson clover had roots over 12" deep. The roots had many nodules on them as well.

 

These cover crops were flown into a seed corn field in NW Indiana in early September. Both the radish and annual ryegrass had roots over 20" deep.

 

There were many earthworms in most of the cover crop fields and in cover crop plots, especially when compared to areas without cover crops.

The Importance of Sunshine in Cover Crop Establishment

On October 18, 2011 the cover crops are looking quite different in one section of the field than the other...the main reasons? The maturity of the soybean variety planted and row width.

In previous posts I have shared about the importance of applying cover crops at the correct time.  I also looked at the difference in how cover crops emerged in corn and soybean fields when aerial applied in the fall of 2011.  In the past several weeks I have traveled over much of Indiana and northwestern Ohio looking at aerial applied cover crops.

Four things I have noticed so far:

1) Aerial applicators seem to be doing a much better job in 2011 than in years past.

2) Correct timing of aerial application into cash crops is vital (that the crops are mature enough for cover crop success).

3) Corn and soybean variety maturity differences can change “success” rates.

4) It appears that row spacing in soybeans makes a big difference, especially in establishing crimson clover.

I was in a soybean field in Jasper County, IN, with Dan Perkins, SWCD Watershed and Conservation Program Specialist. It looked as though about one-half of the field had been harvested a week or so earlier than the other half because the cover crops were considerably taller and more dense in the earlier bean maturity area than in the later bean maturity part of the field.

But I was wrong about the harvest date…there was only 1 day harvest difference between the two areas.  One difference was the genetic maturity of the varieties of soybeans.  One variety was a 3.0 maturity and the other was a 3.4 maturity. Incidentally, the farmer reported that the two varieties yielded virtually the same.

Another key observation was made with differences in row spacing, particularly with crimson clover.  In the 15″ and 30″ rows the crimson clover looked very good with an even stand and good growth. But in the fields with 7″ rows the stand did not look quite as good. In fact, in some fields with 7″ rows, the crimson clover was hard to find.  The annual ryegrass and the cover crop radishes had a better stand than the crimson clover in the 7″ spaced rows, yet even they had considerably less growth than in the wider spaced rows.

Why does this matter?  It matters because P-H-O-T-O-S-Y-N-T-H-E-S-I-S matters.

In many eastern corn belt soybean fields that the cover crops were aerial applied in are quite varied this year.  Overall there has been very good moisture and adequate time for the cover crops to germinate and grow, but the rate of growth has varied considerably based on how mature the soybeans were at planting date. While the soybeans have been off for over a month as of this posting you can look at the photo taken on November 22 and still see a difference in cover crop “coverage” and growth.

The stands have been good over all but the amount of growth from that stand seems to vary a bit more than in past years.

The take-home message is that we need to make sure that crops are mature enough when applying cover crops.  And if planting into fields with 7″ rows, maybe wait until 75% leaf yellowing to assure more sunlight hitting the ground when the seed is germinating.  Sunlight really is important…just like my 9th grade biology teacher said it was.

This photo, taken November 22, 2011, shows cover crops flown into corn, a 3.4 maturity soybean that was drilled in 7" rows (center), and a 3.0 maturity soybean planted in 30" rows (top). The same cover crop was flown into all three sections on the same passes of the plane. The difference...Sunlight getting to the soil.

 

Cover Crop Field Day Set at Robison Farms

CISCO Seeds, Robison Farms, and Dougherty Fertilizer are sponsoring a Cover Crop Field Day and Root Dig at the Greenwood, Indiana farm. If you’ve not had an opportunity to see cover crops in a real life farm setting, this will be a great meeting for you . There will be multiple species available to look at and expert agronomists on hand to answer questions.

 

When:

Wednesday, November 30, 2011 from 2-4 P.M.

Location:

Corner of Five Point Road (300 East) and Main Street (Rocklane Road) east of Greenwood, IN

Contact:

If you have questions or need further information contact  Don Robison at donrobison@ciscoseeds.com or 317-357-7013

  • Rain or shine we will have a gathering (call if the weather is bad for “plan B”)

 

Cover Crop Field Day Highlights

Come see ten different mixes and/or species of cover crops in a large plot setting.
  • 1100’ lineal feet of cover crop plots
  • 10 different mixes or straight species shown
  • guaranteed weather! (not saying what kind)
  • working with NRCS, SWCD, and Dougherty Fertilizer
  • root digs (weather contingent)
  • Cover Crop Agronomists on hand for tours and Q/A sessions
  • See over 150 acres of various Cover Crops withing 1/2 mile of plots

 

Purpose of the cover crop field day

To see different species of cover crops in a real to life situation. This was a soybean field that had the cover crops applied over the top of the standing crop at roughly 50% leaf drop.

 

Species You Will See

 

  • Radishes
  • Turnips
  • Crimson Clover
  • Oats
  • Winter Rye
  • Annual Ryegrass
  • Austrian Winter Peas
  • Several Mixes including the above species

 

 

 

Directions:

From Indianapolis

  • Take I-65 South to Exit 99. Turn Left at end of ramp and travel 1.5 miles east to the plots

From Louisville

  • Take I-65 North to Exit 99. Turn Right at end of ramp and travel 1.5 miles east to the plots

From Columbus, OH

  • Take I-70 West to Indianapolis, follow 465 South to I-65 South to Exit 99. Turn Left at end of ramp and travel 1.5 miles east to the plots

From Terre Haute

  • Take I-70 East to Indianapolis, follow 465 South to I-65 South to Exit 99. Turn Left at end of ramp and travel 1.5 miles east to the plots

 

Just down the road we plan on digging another pit where Annual Ryegrass and Appin Turnips were applied after hog manure was knifed in after wheat.

What if a cover crop dies over the winter…was it still valuable?

As I take phone calls and conduct meetings I ask producers if they want to have the cover crop they are choosing to overwinter or die during the winter.  I’d guess that the answer as split 50/50. The biggest reason for wanting the cover crop to die is that producers don’t want to have “to mess” with killing a crop in the spring of the year.  Other advantages that folks mention is that they believe that the soil will be warmer if there is not a living cover in the field.

This mixture was planted on time but had very little moisture in the fall of 2010. All things considered it is a beautiful stand. However, the crimson clover is so short that I hope that it overwinters so the producer can get "maximum" nitrogen benefit for the 2011 corn crop.
On November 17, 2010 we found annual ryegrass roots 40" deep after just 10 weeks of growth. We want this field to overwinter...but we already have accomplished nutrient management goals by holding nutrients from the manure applications. If the field overwinters I believe we may find roots 70" deep when we dig in April 2011.

Advantages of having a “short-term summer/fall cover crop” is that you should still control the majority of the winter annual weeds, many legumes will still produce a good amount of nitrogen before winter (Austrian Winter Peas, Cowpeas, Crimson Clover, Berseem Clover, Field Peas, etc…).  Radishes and turnips will do their nutrient scavenging and plow pan cracking work before the killing freeze too. Even annual ryegrass might have produced a pretty good root system before it goes winter dormant (or dies) depending on the seeding date/fall growth. (See  details of what we found in an annual ryegrass field in the fall of 2010.)

So what would be the advantage of a winterhardy cover crop?  Improved spring erosion control, more living roots in the soil for a longer time period, more spring-time earthworm activity, more nitrogen produced (from legumes) and over a longer time period, minimal soil temperature change (versus a dead cover crop or no cover), a longer grazing time period, to name a few.

Disadvantages of the crop overwintering would include the risk of a very wet spring causing trouble getting the crop killed, possibly cooler spring soil temperatures, and possibly some reasons that don’t come to mind.

If using a legume like clover it seems to be advantageous to have it overwinter, however Berseem clover possibly produces the most N of any legume…and it is sure to winterkill in Midwestern winters.  And I like Berseem clover when it fits the producers situation.

So, does it matter if the cover crop survives the winter…even if it dies when you expected it to survive?  My answer is that there are still benefits on most cover crops IF they were productive in the fall/winter.  If you have a late planted cover crop that has minimal growth in the fall and then it dies…you possibly “wasted” money.  Do your best to plant cover crops in a timely fashion.  Give them the best opportunity to do their best!

When to aerial apply cover crops into corn

Corn should be dried "up to the ear" for best results when utilizing aerial application.
Corn should be dried "up to the ear" for best results when utilizing aerial application.
Approximately 50% of the sunlight should reach the ground in the field when aerial applying cover crops into corn.
Approximately 50% of the sunlight should reach the ground in the field when aerial applying cover crops into corn.

A few years back many said “August 15-25” was the right date to aerial seed cover crops into corn.  However, we found out very quickly that “dates” cannot be set…but timing can be.  While we know that August 15-25 often can be correct, we also know that following the calendar (like in the 2009 crop) can be a mistake.  So let’s set a few guidelines that should help all of us have better success when aerial applying cover crops into standing corn.

 

 

Guidelines for success when aerial applying cover crops into standing corn:

  • Aerial apply cover crops when the corn plant is dried approximately to the ear.

 

  • Aerial apply cover crops when approximately 50% of the sunlight can reach the ground between the rows.  (Walk in the field a few rows to determine this).

 

  • For success, do not fly cover crops into corn that is immature (still very green).  The seeds will most likely germinate and then mold (not enough sunlight to conduct photosynthesis and too moist of conditions).

 

When is it too late to aerial apply cover crop seed into standing corn?

  • You need 5-6 weeks of growing time for cover crops going into the winter for best winterhardiness and performance.

 

  • Winter Cereal Rye is more “flexible” than annual ryegrass or other cover crops when it comes to the lateness of application.

 

  • If corn will be harvested soon after an aerial application can be made, consider the cost of other types of cover crop applications (i.e. drilling the cover crop in after harvest).  Utilize the lesser expensive application.