Plant Cover Crops

Learning about the benefits of planting cover crops.

nitrogen production

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.

Planting into “Out of Control” Peas – The Rest of the Story

In September 2011 I posted about an Ohio farmer that planted into “out of control” peas and shared about his story of how the field was looking pre-harvest.  I have recently visited with Dave (the producer) and he shared the information that a number of you asked for…and also surprising yield data. Dave farms with his father-in-law Ron in Mercer County, Ohio near Rockford (NW Ohio).

Sometimes it takes courage to farm with cover crops! Dave and his father-in-law Ron planted with confidence as the ground was "very mellow" compared to other ground without a cover crop.

Here are Dave’s observations and the 2010-2011 field history:

  • Hog Manure applied late summer of 2010 – 5000 gal/ac
  • No other fall fertilizer
  • N-Vest Groundbreaker Mix (Austrian Winter Peas and GroundHog Radish) planted Labor Day weekend 2010

Peas that survived – and other weeds, wheat, clover, etc. – were sprayed (after a wet, wet spring) on June 2, 2011.

________________________________________________

Herbicide/Insecticide Mix: (rates per acre)
20 gal Water
Alliance – .2 gal   (1 gal/100 gal water)
Roundup WeatherMax – 44oz
Weedone 650 – 1pt
PowerLock Surfactant – 6oz
Baythroid (insecticide) – 2oz

Corn was planted on June 3, 2011.

Additional Fertilizer applied (in addition to nutrients from manure and N from peas)

20 gal/ac 10-34-0 starter fertilizer with 1qt/ac zinc

40 gal/ac 28-0-0 side dress with Agrotain N stabilizer

Results

Even though several acres in the area were too wet to plant this field of peas was in great shape as you can see the row closed "perfectly" behind the planter.

Weigh wagon test showed 215 bu dry yield.  Dave guesses the whole field average was between 200-215 dry (he has no scales at home to check weight of entire crop).
Dave also thinks that the yield was 10-15 bu better that most of their other corn (w/o manure and w/o cover crops).

The seed placement of this no-till planting into the peas was "near-perfect".

All things considered…the wettest spring in Eastern Corn Belt History, late planting date, planting into 3+ foot tall peas, < 1″ of rain in the month of July (with 22 days 90 degrees or more), a wet fall that delayed harvest..and the result was over  200 bushels/acre.  I’d take that everyday for that part of Ohio, and so will Dave and his father-in-law Ron.

The roots on the peas were massive by early June. Don't expect this in most years but this certainly did not hinder planting, getting a good stand, or attaining a very high yield!

Other observations from Dave:

Positives:

Better soil structure

Deeper root penetration by corn roots

Great seedbed to plant into

Great soil cover after cover crop was killed

Better water retention thru the dry months

Nutrients saved from hog manure

Negatives:

Too much growth in wet spring

Took a lot of time to plant due to pea growth

 

Thanks Dave for sharing your story!

Cover Crops in the Great Plains – a view from a long time cover crop user- Part 2

In this cover crop post I again quote Paul Conway from Kansas, who is giving his input on cover crops in the Great Plains. In this article, Paul shares his experience with Austrian winter peas, field peas, chickling vetch, and hairy vetch.

Dave,

Austrian Winter Peas: I have limited and disappointing experience with Austrian Winter Peas.  They always winter kill and they must be planted at an inconvenient time.  It seems that the areas where they do well do not follow a simple geographical line.  Austrian Winter Peas do very well about 60 miles south of me in central and southern Kansas.  Ironically, they seem to do fine in the Nebraska panhandle, which is much colder than we are. I think consistent snow cover makes the difference.

Field Peas: also know as Canadian field peas or forage peas. I’ve grown these in early fall with oats and forage radish. I don’t know how much nitrogen they fix but they do winterkill by early winter –  mine haven’t died yet – probably consistent lows in the middle teens will do it.

I also plant them in early spring the same time as oats, killing them for June planted cash crops.  Mowing after flowering will effectively kill peas.  Where peas shine is in mixes and in cool climates.

The pea/oat or pea/triticale is excellent for haylage or silage. These mixes have the same benefits for livestock farmers as the soybean/summer grass mixes.

In much of the Midwest and east, double cropping is possible, oat/peas followed by soybean/milo or sorghum-sudan.  Further north, the oat/pea mixes would mature too late.  In that regard, I think that field peas could be managed as a summer annual (like soybeans) in the Great Lakes states, upstate New York, Pennsylvania, and New England.

Peas can handle routine summer temperatures in the low-mid 80s. Peas can be grazed. Peas aren’t shade tolerant so they don’t do well when sown into row crops.  Frankly outside the mixes I think the clovers may be more versatile.

Chickling Vetch: Also known as “AC Greenfix.” It will fix nitrogen faster both in the fall (it winterkills about the same time as the peas) and in the spring.  AC Greenfix seed is more expensive and harder to plant due to it’s shape.

Hairy Vetch: As you know, hairy vetch is the strongest nitrogen fixer among the annuals.  Hairy vetch easily fits into vegetable rotations. I have seen two foot vine growth and numerous fat nodules on vetch in early-mid April after a mildly wet fall and an early spring.  It will be harder to fit into field crop rotations, especially corn-soybeans.

Here the optimum time to plant hairy vetch is September, but it can be planted as late as mid October.  It needs minimal soil contact which isn’t a problem in a normal fall. A dry September/October, like I had this year, is a problem.

I know that you have some experience with flying in hairy vetch into maturing corn or soybeans.  Another option is to plant it very late (mid-late November) and hope it doesn’t germinate until the soil warms up in late winter-early spring.   I don’t think people realize how versatile hairy vetch can be.  In the northern areas suited for field peas (see above) hairy vetch could be managed as a summer annual. [I have seen hairy vetch flower, drop seed which stays dormant during a hot dry summer – Dave’s EMPHASIS HERE – this is why I caution growers about Hairy Vetch.]  When the weather cools down in late August the vetch seed sprouts.  It is still warm then through September and early October with temperatures similiar to the Great Lakes states and New England in the summer.  So why couldn’t vetch be planted in early summer in these areas?

Years ago I planted hairy vetch in April between wide rows of vegetables just to see what would happen.  I remember lots of growth by July, despite a hot dry summer. The soil under the vetch was cool and moist.  The vetch did not grow enough to fix much nitrogen by May but it may have fixed enough nitrogen for mid-summer planted crops.

In 2012 I will plant hairy vetch and other vetches (purple) in the spring and record how they do.

Finally, new cultivars of hairy vetch come out which may have promise.  I will try a new variety called Purple Bounty, which is supposed to mature two weeks earlier but with less winter hardiness.

 

“Where is my nitrogen?”

Austrian Winter Peas add as much as 100 untis of nitrogen to the soil if they hav egood growth in a good stand.

This question keeps coming up on a regular basis in cover crop meetings….”where is my nitrogen?”

There are a number of things we know:

  • Legumes produce N and some of that N is available for the next crop.
  • Most cover crops scavenge N.  Some of that N is available for the next crop.
  • Some of the N is not available for the next crop.

How do you determine how much N is available for the next crop?

According to Managing Cover Crops Profitably: (p. 22)

 How Nitrogen is Released

How much N will soil really acquire from a legume cover crop? Let’s take it from the point of a freshly killed, annual legume, cut down in its prime at mid-bloom.The management and climatic events following the death of that legume will greatly affect the amount and timing of N release from the legume to the soil. Most soil bacteria will feast on and rapidly decompose green manures such as annual legumes, which contain many simple sugars and proteins as energy sources. Soil bacteria love to party and when there is lots to eat, they do something that no party guest you’ve ever invited can do—they reproduce themselves, rapidly and repeatedly,doubling their population in as little as seven days under field conditions (306). Even a relatively inactive soil can come to life quickly with addition of a delectable green manure. The result can be a very rapid and large release of nitrate into the soil within a week of the green manure’s demise. This N release is more rapid when covers are plowed down than when left on the surface. As much as 140 lb. N/A has been measured 7 to 10 days after plowdown of hairy vetch (363).Green manures that are less proteinrich (N-rich) will take longer to release N. Those that are old and fibrous or woody are generally left for hard-working but somewhat sluggish fungi to convert slowly to humus over the years, gradually releasing small amounts of nutrients. Other factors contribute significantly to how quickly a green manure releases its N.Weather has a huge influence.The soil organisms responsible for decomposition work best at warm temperatures and are less energetic during cool spring months. Soil moisture also has a dramatic effect. Research shows that soil microbial activity peaks when 60 percent of the soil pores are filled with water, and declines significantly when moisture levels are higher or lower (244).This 60 percent water-filled pore space roughly corresponds to field capacity, or the amount of water left in the soil when it is allowed to drain for 24 hours after
a good soaking rain. Microbes are sensitive to soil chemistry as well. Most soil bacteria need a pH of between 6 and 8 to perform at peak; fungi (the slow decomposers) are still active at very low pH.Soil microorganisms also need most of the same nutrients that plants require, so low-fertility soils support smaller populations of primary  decomposers, compared with high-fertility soils.Don’t expect N-release rates or fertilizer replacement values for a given cover crop to be identical in fields of different fertility. Many of these environmental factors are out of your direct control in the near term.Management factors such as fertilization, liming and tillage, however, also influence production and availability of legume N.

So while know that cover crop legumes produce nitrogen we also know that the nitrogen will be released at different times and in different amounts according to the circumstances in individual fields and with different management practices.

In 2010 many producers across the Midwest  shared that they could see a “big difference” in their corn yield where they had a legumes as a cover crop.  While we cannot easily (or maybe not totally) quantify the pounds of N available for the next crop we can count on some level of improved performance.  Can we reduce our inputs?  Maybe.  Can we always get higher yields?  No.  Can we anticipate an improved yield?  Probably.  Some folks will tell you “yes” to those questions!  Some others will have a different experience.

So what do you do?  Plan for success, scout your corn, use a pop-up and/or starter with nitrogen…and scout…oh, yeah, I guess I already said that!

Cover Crop plots in December-What can we tell now? part 2

In this post we look at two more videos of mixes on December 2, 2010.  This first mix in this session is of Austrian Winter Peas and GroundHog Radishes.  The seeding rate is 30# Peas and 5# of Radish per acre.  The main thing we observe in this plot is the larger radishes than we saw with the mixes of annual ryegrass, crimson clover and radishes.  Now, in this mix there are more radishes than in the previous two plots (see previous post).  So we have 2-3#/acre more radishes yet larger radishes.  Again, this is NOT scientific, but it sure appears that the radishes, which are luxury consumers of nitrogen, are much larger…thus I conclude, have been fed more  nitrogen from the peas.  It was quite surprising to me to see how much the peas have grown sine I last saw the plot in early November.  The cooler weather seemed to really allow them to grow at a faster pace.

In the second video on this you will see the plot that appears to have the most nitrogen produced.  This mixture is of 17#/acre of AU Robin Crimson Clover and 5#/acre of GroundHog Radish.  In this plot the radishes are noticeably larger in girth and above ground growth.  In fact as you look across the plot it is obvious that this plot is the most “robust” in its growth. In the spring of 2011 I anticipate that the AU Robin Crimson Clover will still be producing more nitrogen.  From previous cover crop field pits we have dug this fall we have found roots on the crimson clover at 24″ deep.  So we have deep rooted cover crops with both items in this mixture as well.

In both of these plots you have excellent nitrogen production and nutrient scavenging!  Personally I like that for a cover crop.  What do you like?

Big Radish fed by Crimson Clover

The video below shows the value of Crimson Clover in a cover crop setting.  Crimson clover has been tested and shown to produce as much as 140#/N after it has been planted after wheat.  The plots in this video were planted around July 29, 2010 by the Jasper and Newton County SWCD folks (Thanks Dan and Rose) at the Churchill Farms near Lake Village, IN.  The mix is called Crimson Cover-All sold in the N-Vest(R) line up by CISCO Seeds.  The planting rate was 21#/acre (approximately 16# Crimson Clover and 5# GroundHog Radish).  There was under 3″ of rain at this site from July 25 through Mid-October.  The soil is a sandy loam.  There was no additional fertilizer put on the plot.  The Radish in this video was weighed at Country Acres in Francesville, IN at 12# 14 oz.  It was one heavy radish…full of nutrients and water!  As that radish decomposes the water and nutrients will be released into the soil for the 2011 crop and for building organic matter.