Blog

Jun 14 2010

Cover Crop Radishes – differences in varieties

On May 29th I planted 6 different cover crop radish varieties in a plot. In those 16 days we’ve had good moisture, and I did apply some 30-0-5 fertilizer around 60 days ago (with slow release N). I had to thin the plots to have 1 radish per 4″ (recommended distance between radishes by those who seem to know those things). I am doing this experiment for three different Oregon companies that sell cover crop radishes. I have this same experiment going on in Michigan, central Indiana, and NW Ohio.

The goal…to identify the “best” cover crop radish. I hope that by planting in spring and late summer, we will be able to choose the radish variety/selection that works best for cover cropping in the Midwest.

I brought 4 varieties up from the plots to show the differences after 16 days. 2 varieties have nice long tubers already. The other two have some catching up to do! I have a feeling that they never will. I’ll keep you posted!

Radish plot 016 — cover crop radish plot...16 days old (and needing weeded!).

Radish plot 017 — 4 different varieties of "cover crop radish." 1 on far left I'll call "Stubby;" 2 just to the left of the stick look promising so far; 1 just to right of the stick I'll call "Shorty;" and the far right selection also looks very promising. all 16 days after planting.

Jun 12 2010

Austrian Winter Peas

Austrian Winter Peas are a good cover crop for producing nitrogen. These peas have better cold tolerance than Canadian Field Peas yet still grow well when planted after wheat or other summer annuals. It’s preferred to plant them in August after the hottest days are normally past. Below I list the advantages and disadvantages of Austrian Winter Peas.

Cover crops May 2010 031 — Austrian Winter Pea flower

Cover crops May 2010 077 — The peas in my garden plots overwintered and grew to over 5 foot tall this spring!

Groundbreaker-peas — Austrian Winter Peas provide a very nice source of Nitrogen.

Advantages

Produces 60-120#/acre N
Generally Winterkills
Easy to kill with herbicides
Mixes very well with Oilseed Radish
Relatively inexpensive to use as a cover crop

Disadvantages

Best to be planted 1/2″ or so
Aerial application provides challenges for stand establishment- but has worked!
Generally Winterkills
Needs 5-6 weeks growth for best results
Only one grazing/harvest can be expected

Jun 12 2010

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.

2009_0909earlySept20090256 — 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.

2009_1213December20090049 — Oats and Radish Mixture following wheat. Hog manure was nitrogen source.

2009_11172covercropsfall20090507 — When properly inoculated, Austrian Winter Peas are prolific producers of nodules (and nitrogen).

2009_11172covercropsfall20090483 — 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.

Cover crops May 2010 010 — 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.

Jun 06 2010

Cover Crop Radishes – What they do

2009_11172covercropsfall20090124 — Cover Crop radishes drill deep into the top soil. Some claim that they break through the plowpan.

Cover crop radishes are “all the buzz” these days in the cover crop world. Cover crop radishes should have fairly large tubers that penetrate the soil and add many benefits. The main benefits are that they enhance percolation and aeration. Additionally they provide food for earthworms like few other cover crops. It is quite common to find 3-5 earthworms per tuber.

2009_11172covercropsfall20090511 — Larger tubers of cover crop radishes "lift" the soil around them, "building" the soil. Note the smaller radish to the right...it is also an effective soil builder.

The question that many producers and researchers are asking is “how big” do the radishes need to be to be effective? My friend Barry Fisher, NRCS Agronomist in Indiana, leans towards several smaller tubers being better than the “State Fair” type that may be confused for a baseball bat! While the larger tubers make newspaper ads and are great for photo ops, I’m not convinced that they are necessary. On the other hand, the larger tubers do a better job of “lifting” the soil around them. It is not uncommon to find soil built up around the larger tubers at least 1/2″. (See photo)

Old radish hole — A hole where a radish tuber had been. Note the lifted soil!

Cover crop radishes scavenge nitrogen and other nutrients from the soil. To achieve the larger tubers it is important to have good fertility like manure or a legume planted with the radishes. If there are few nutrients to scavenge, the radishes will rarely become very large.

The main benefits of cover crop radishes

Cover crop radishes:

scavenge nutrients from the soil (especially nitrogen).
penetrate the soil, therefore reducing compaction.
enhance soil percolation and aeration.
provide an excellent environment for earthworms.
provide deer and cattle an excellent wintertime feed.
die in the winter (around 25-29 degrees).

Cover crop radishes may also:

increase yields on corn by as much as 9-10 bu/acre (recorded in central Indiana).
reduce soybean cyst nematode populations.
improve control of winter annual weeds (this is usually the case).

When planting cover crop radishes:

Drill 1-3# or broadcast 3-5#/acre for larger tubers.
Drill 3-5 or broadcast 6-10#/acre for more, smaller tubers.
Use improved selections (varieties) for more consistent results.

The main detriments of cover crops radishes

Cover crop radishes:

stink when they deteriorate!
may head out if you plant them too early in the summer. A late-summer planting (August-September) works best.
need 6-10 weeks of growth for best results.
may contain hard seed, which when sown in the late-summer, may germinate in the spring.
may develop very deep roots in very sandy soil…which may get into field tiles…even 32″ deep tiles

Jun 05 2010

Earthworms…valuable resource on farm ground

Earthworms are exceptionally valuable builders of healthy, fertile topsoil. Jill Clapperton stated that a good sign of a healthy topsoil was that a “shovel-full of soil” should have 8 earthworms in it. In my field diggings I have found anywhere from ZERO to 10 erathworms per shovel-full. I found 10 in crimson clover, 8 in annual ryegrass, 7 in my Austrian winter peas, 10 in my annual ryegrass/crimson clover mix and ZERO where I had no cover crop.