turnips

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.

Jul 17 2012

Harvesting Cover Crops for Emergency Fall Forage

Need Feed?

Corn - Drought stricken 2012 — Many producers across the Midwest and beyond have very poor corn. Grain and Silage yields will be significantly lower than normal in 2012.

Harvesting cover crops for emergency fall forage may be able to play a major role in lessening the impact of the 2012 drought disaster for livestock producers. As I traveled from Indiana to eastern Iowa and through Wisconsin I saw dry ponds, cracked soil, nearly dead alfalfa, completely brown pastures, and an exceptionally poor corn crop.

I have received phone call after phone call from dairy and beef producers asking what cover crops they can use to provide food for their animals this fall and winter. Below I have listed a variety of choices that may work well for producers needing feed (if we get rain). By the way, these choices are also excellent cover crops.

Fall Forage Fast- Mechanically Harvested

Sudangrass or Sorghum X Sudangrass

Both of these would be choice 1-A and 1-B. However the producers in Texas have been experiencing drought for the past few years and seed supply is exceptionally tight. Choose BMR varieties if you can find them.

Spring Oats/Spring Triticale

Ingham County Cover Crop Plot — This photo was taken south of East Lansing, MI in April 2010 and shows Oats in the center with Cereal Rye to the left and Spring Triticale to the right.

This is not a “sexy” choice but it is a very good option. Oats sown in July and August will out-produce all of the winter cereal grains if a fall harvest is desired. I have worked with Ed Ballard from the University of Illinois and Gary Wilson from Ohio State University Extension for a number of years on summer seeding Oats and found great success almost every year.

Stan Smith from OSU Extension is a real believer in summer seeding oats as seen in this excellent article. Seed the Oats at 2 bu/acre and fertilize with 50+ Units of N or manure equivalent. Spring Triticale will behave very similarly to Oats when summer seeded.

Oats and Crimson Clover

Crimson Clover can make a great fall forage and cover crop — From this photo of crimson clover, you can see the potential forage value planted with oats (note the field in the background).

I really like this mix because it will be higher quality than plain oats. Plant the oats in the grain box and the crimson clover in the small seed box. Plant the oats at 2 bu/acre and the crimson clover at 5-8#/acre.

Nathan Anderson of Cherokee, Iowa (NW Iowa) planted this mixture in 2011 and had very good success. While taking one cutting for hay and grazing 2 times in the fall/winter, he showed a profit of nearly $140/acre in beef production (weight gain) and hay produced.

Make sure that the crimson clover is inoculated and do not plant the crimson clover more than 1/2″ deep.

Oats and Cereal Rye (or Winter Triticale)

Oats and Rye — Oats (left) and Rye (right) planted in August show the value of Oats as a fall forage in this photo taken in October 2011 in NE Indiana.

Harvest the oats in the fall and the cereal rye in the spring. I’d look at 2 bu/acre oats and 1 -1/2 bu/acre on the cereal winter rye or triticale. Consider adding 5-8# of Crimson clover to this mix as well.

Oats (or Spring Triticale) and Peas (Forage or Austrian Winter Peas)

Plant a 50/50 mix of this combination for high quality fall forage. Be sure to inoculate the peas. Plant this mix 1 1/2 -2″ deep for best success.

Annual Ryegrass/Annual Ryegrass – Crimson Clover Mix or Italian Ryegrass

Annual Ryegrass for grazing or harvesting — Annual ryegrass makes great fall and spring feed. It loves nitrogen, so apply plenty of manure. Add crimson clover to this, and WOW!

Annual Ryegrass or Italian Ryegrass will not produce the tonnage that the spring cereal grains will. Ryegrass needs cooler temperatures, more moisture, and more fertility than the spring cereal grains need. The main benefit is that you can get a very high quality forage…just not a lot of it unless you have the moisture, cooler temps, and higher fertility. Maybe in the southern parts of the Midwest and further south this can be a good option. Italian Ryegrass will not grow as aggressively in the fall as Annual Ryegrass will.

Spring or Winter Barley

Barley is a multipurpose cover crop that can be beneficial to hog, dairy, and beef producers. It is a wonderful grain to use for feed and it is harvested for grain in June. The haylage would be harvested in May with plenty of time to plant corn silage or Sudangrass. Spring Barley planted in July/August will act like Oats and spring Triticale. Winter Barley will act more like cereal rye or winter Triticale. Plant 2 bu/acre for grain production and 3 bu/acre for forage production. Use less N than you would with Wheat or Ryegrass.

Harvested Winter Barley from Dairy Farm — Spring or Winter Barley is also an option. Barley grain can be fed pretty similarly to corn and be harvested in June.

Apr 14 2012

Cover Crop Turnips – A Good Choice Over Radishes?

Cover Crop Radishes or Turnips as a Cover Crop – or Both?

Cover crop radishes certainly receive a lot of press. I have researched them quite a bit over the past four years. On this blog alone I have over 20 posts about radishes. They are fun to take photos of, dig around in, research, and even play baseball with.

It is hard to pick up a publication that mentions cover crops and not read about radishes and their benefits. Some industry and university cover crop research leaders like Steve Groff and Dr. Ray Wiel (University of Maryland) have researched radishes for over 10 years.You might say that cover crop radishes are the “Rock Star” of cover crop species these days.

What About Turnips?

The Oats are nearly 30" tall and the turnips are around 18" in this Oactober photo. The Cereal Rye was about 6" tall at this time. This mixture was planted in late August and the photo was taken Oct 22 - approximately 8 weeks after planting. My daughter Grace was the model.. — The Oats are nearly 30″ tall and the turnips are around 18″ in this Oactober photo. The Cereal Rye was about 6″ tall at this time. This mixture was planted in late August and the photo was taken Oct 22 – approximately 8 weeks after planting. My daughter Grace was the model..

Why are turnips used as a cover crop so little compared to radishes? Are they the “ugly step-sister” of the Brassica family?

Let’s look at some of the benefits of turnips. Some newer varieties (Appin in particular) provide a bulb that is almost entirely in the soil and a deep root system (though a smaller bulb/tuber than the radish).

Benefits of Turnips

Turnips are very palatable for grazing cattle and sheep.
Most turnips survive the winter and hold onto nutrients into the spring (longer than radishes).
Turnips sequester nutrients in a similar fashion and amount as radishes (see data below).
Turnips are easy to kill in the spring.
Turnips do not have the odor problems that radishes have (therefore they can be planted more “safely” in areas closer to towns or neighbors).

“Problems” with Turnips

Not all turnips are created equal. The old purple top (or that type) turnip and even the tankard type turnips have very little of the bulb in the soil – thus less soil activity.
Most turnips survive the winter and then need to be killed in the spring. Yes this can also be a benefit.
The turnips “bolt” in the spring and want to produce seed. Kill them as early as possible.
Turnips will overwinter in the spring. The turnips above flowered out in March 2012 in central Indiana. This is nearly 5 weeks before “normal”

Frequently Asked Questions

If we mix turnips and radishes together, is that okay? YES – for grazing or for just using as a cover crop.
If we plant turnips instead of radishes is that okay? Yes – just be aware of the differences and that the turnips will most likely survive the winter.
What if we are just looking to graze and only care some about the cover crop? Choose turnips.

Brassica types Ayres Farms - Fall 2010 — These three brassica types were collected from a Loundonville, OH farm in the fall. Pasja Hybrid Brassica (L); GroundHog Cover Crop Radish (C); and Appin Turnip (R). Note the difference in tops versus tubers.

Nitrogen tested in Radishes/acre from Loudonville, OH dairy farm averages 200 units of N (data collected November 2010)

Nitrogen tested in Appin Turnip/acre from Loudonville, OH dairy farm showed nearly 300 units of N (data collected November 2010)

The turnip tops had nearly 200 units of N/acre. This was NOT scientific but it is instructive that turnips are an excellent scavenger of N.

Nov 12 2011

Nutrient Scavenging Cover Crops – How much good are they doing? It depends.

Meet the Cover Crop Scavengers

Over the years I have worked with cover crops I have recommended that producers use “scavengers” like Annual Ryegrass, turnips, cereal rye, winter barley, oats, and cover crop radishes. These cover crops do a very good job of capturing excess nitrogen and other nutrients and keeping them from reaching the ground water or running off with surface water. When the nutrients are scavenged they are available for the subsequent crop.

Most of these scavengers are “luxury consumers” of nitrogen and a few of them are also “luxury consumers” of phosphorous. These are ideal to use on land where manure is applied. They also work very well when grown with a legume like crimson clover, hairy vetch, chickling vetch, and Austrian winter peas.

However, if limited amounts of nitrogen are available how will these scavengers perform?

The answer: not as well.

My answer is subjective but based on observations that I will show you via some photos.

Observation 1

DSCN4335 — It is easy to see where the manure was knifed in in this field. But how much more N is being taken up where it is darker green? We'll be doing tissue tests soon to determine that.

The first observation is where hog manure was knifed in after wheat had been harvested. The photo shows that the cover crop (Annual ryegrass and Appin turnips) looks considerably darker where the manure had been applied. We will soon be taking tissue samples to see what difference there is in the amount of N, P, and K are in the plants. We also anticipate a future post showing a root pit view of the root growth difference (if any).

Observation 2

DSCN4406 — The "yellow" strips are pretty obvious in the cover crops in this seed corn field. It is not obvious where the corn rows were but I expect the lighter strips are above where the corn row had been.

The next observation comes from a seed corn field in north western Indiana near Demotte in Jasper county. The main area of difference in N uptake is found where the male corn rows had been cut out this summer after the female rows had pollinated. The difference is color was not as dramatic as it was in the previous situation but there was a clear difference in color and the amount of growth (considerably more developed) of the cover crop.

Observation 3

DSCN4696 — The left half of this photo had 35#/acre of N but had no legume to feed the radish. The right half of the photo shows the significant color and growth difference when radishes are grown with crimson clover (and the 35# N/acre).

The next field is near Edgerton in NW Ohio. This field had three different applications being trialed. One area had a crimson clover and GroundHog radish mixture, another area had an Austrian Winter Pea and GroundHog Radish mixture. In between these mixtures was a strip of Tillage cover crop radishes with no legume but with around 35 units of nitrogen applied (the ~35 # of N was applied across the whole field). If you attend many cover crop meetings you will hear speakers tell you to apply 35-50 units of N on radishes if they are sown without a legume or without manure applied. After seeing this field I believe we are underestimating what kind of N we need to apply for “best” results as the radish only strip had considerably smaller radishes with much less tuber growth and more “yellow leaf”. The area with the crimson clover/GroundHog Radish Mix was by far the darkest green and had the largest radish growth. However, even though the peas did not look as impressive as the crimson clover, the radish growth was significant and much darker green than the radish area grown without any legume.

Observation 4

DSCN4698 — Not only does the crimson clover add nitrogen to the soil it also greatly enhances the soil structure. The soil on the left came from where there was only radishes planted. The soil on the right had crimson clover and radishes mixed together.

Another observation from this field was that where the radishes were grown with the crimson clover the soil had a much improved structure over the soil where only radishes were grown. The massive amounts of crimson clover roots (with an exceptional amount of nodules on them by the way) gave the soil a much better texture. See a very descriptive video here. These soils are “Williams County Clays” or “NW Ohio clays” and are well known for their tightness and poor drainage. As the farmer Ryan Sanders said after seeing the results of this experiment… “I will never plant radishes alone again.”

Jun 14 2010

Cover Crop Radishes and Turnips…what are their differences?

Radish plot 010 — Cover Crop Radish on top and forage Turnip below. There is quite a different root structure!

Radish plot 014 — Note the number of root hairs on this turnip tuber. It may have more root surface area than the radish.

The cover crop radishes and forage turnips that I accidentally planted in my wife’s wildflower garden just over 4 weeks ago lets me make some observations about the differences between the radish and turnip roots.

The radishes have a fairly “hairless” root that has very quickly reached 7 ” deep.

On the other hand, the turnips are only 4 inches deep.

So which one is better for the soil? Look at the fibrous roots on the turnip. While the turnip is not as deep, I’d estimate it has more root surface area than the radish!

Unfortunately (or fortunately) I planted several radishes and turnips in the front flower garden (sorry honey). But that allows all of us to keep tabs on the differences as the summer progresses!