Plant Cover Crops

Learning about the benefits of planting cover crops.

cowpeas

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.

Cowpeas-some love, some…

Cowpeas are an enigma for Midwestern producers.  Sometimes referenced as a “summer soybean,” cowpeas need to have hot weather and adequate moisture to have the best success.  Cowpeas do exhibit  good drought tolerance. If there is a dry summer, cowpeas should be planted by 4th week of July.  Inoculating cowpeas is vital for success.  Cowpeas need to be planted ¾ -1” deep and have excellent weed control to establish well.  When a good stand is established and growing, cowpeas can produce 70-150# nitrogen/acre.   The past few years cowpeas have been expensive to use.

Advantages of Cowpeas

  • Produces N
  • Excellent for forage
  • Winterkills
  • Excellent summer choice
  • Improved drought tolerance
  • Works well mixed with oilseed radish

Disadvantages of Cowpeas

  • Expensive in recent years
  • Needs hot weather to excel
  • Winterkills

Plant Cowpeas at 60-120#/acre.

Cover Crop Selection – What to plant after wheat or other cereal grains?

I was in a meeting yesterday and the gentlemen from SWCD asked me:

“What should we recommend for our producers to plant as a cover crop after the wheat comes off?”

After running through a number of scenarios I determined that I’d better make sure I don’t confuse folks with too many ideas.  So, here are a few scenarios that I hope you find useful.

If you want to scavenge Nitrogen and other nutrients, then a good choice would be Oats and Radishes mixed together.  This mix generally should be planted at 1 1/2 bu Oats and 2-5# of Oilseed radish/acre.  This mix also requires manure or around 40# N applied for it to be the ideal mix for this situation.  This mixture will die in the winter and provide excellent winter annual weed control.  Best planting time is Mid August…so you have plenty of time to get weeds killed and manure applied.

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Sudangrass and Sorghum-Sudangrass are excellent crops after wheat if you need animal feed.

If you have livestock to feed, other great nutrient scavengers to plant after wheat are Sudangrass, Pearl Millet, or Sorghum-Sudangrass. These summer annual grasses require 100+# of N or equivalent manure. Tonnage of 4 1/2 tons Dry matter/acre have been common in northern Indiana following wheat the past three years. These grasses are excellent soil builders as well. Mycorrhizae fungus find the roots of these plants a very good place to multiply and build soil structure.

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Oats and Radish Mixture following wheat. Hog manure was nitrogen source.
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When properly inoculated, Austrian Winter Peas are prolific producers of nodules (and nitrogen).
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Oilseed Radishes are "nutrient sorage facilities"! These big tubers take in significant amounts of nitrogen and other nutrients.

If you want to produce nitrogen and also scavenge nutrients as well, then an excellent choice will be Austrian Winter Peas mixed with Oilseed Radish .  This mixture works very well without the addition of additional nitrogen.  Count on the peas to deliver 60-120# of N and the oilseed radishes to keep most all of it in the top soil root zone. This mixture does a great job of controlling weeds.  The radishes will die in the winter and the peas will “probably” die too…depending on your location, planting time of the mixture, and snow cover.  If they overwinter they are easily killed in the spring.

If you are looking mainly for nitrogen production with a species that will winterkill, then choose cowpeas.  The past few years cowpeas have been very expensive to plant.  Be sure to check pricing and also be sure to inoculate the seed at planting time.  Sow 60-100#/acre of cowpeas.

If you want the nitrogen production with a crop that will overwinter, then crimson clover is a top choice.  Excellent new varieties have come on the market the past few years.  Be sure to inoculate this seed as well. Sow 20-25#/acre of crimson clover.

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Crimson clover planted after wheat is an excellent nitrogen producer.

There are several other options but these will certainly give you a good start in making selections.