oats and radishes

Dec 29 2012

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.

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

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.

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.

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.

Nov 10 2011

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

DSCN4311 — 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

DSCN4334 — 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.

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.