When the last load of corn silage is packed away, it can feel like the biggest job of the season is done. But there’s still plenty to do in the fields before winter.
Manure needs to be hauled. Nutrient plans need to be evaluated. And for some acres, there’s a decision to make about whether a cover crop goes in.
Those decisions can be easy to push down the list after a long harvest. But what happens in the field this fall can have an impact well into the next growing season.
For Matthew Oehmichen, part owner of Short Lane Ag Supply, fall is a chance to look beyond getting corn off the field and start thinking about what those acres need heading into 2027.
Corn Silage Pulls Nutrients
Corn silage takes a lot of nutrients off the field, and Oehmichen says potassium is one producers can overlook.
“A lot of people do not account for fertility removal off those fields,” he says. “You come in, you whop it all off, and you don’t leave it lying. You’re taking it all off the field. All of the nutrients captured in those tissues are removed, and then they go off to feed the cows.”
Corn needs plenty of nitrogen, but it also pulls a significant amount of potassium from the soil as it grows. Oehmichen estimates 7 to 8 pounds of potassium can leave the field with every ton of corn silage. At 18 to 20 tons of silage per acre, those numbers add up quickly.
“Corn draws up a lot of nitrogen, absolutely, but it pulls a heck of a lot of potassium out of the ground,” he explains. “It wants to grow big, it wants to grow green, so it’s going to pull all that potassium out, then you cut it and it’s off the field.”
Potassium plays a role in plant strength, standability and disease tolerance, so replacing what leaves with the crop is worth considering.
“If you have a plant that doesn’t have good potassium levels, the tissues are actually weaker,” he says. “They’re more susceptible to disease when they get a little scratch in them, and they might not grow as leafy or as vibrant as you want them to be.”
Once the corn is off, Oehmichen says it’s a good time to look at the fertility plan and figure out where nutrients need to go back into the field.
“At the very least, if somebody wanted to maintain fertility marks where they felt like they weren’t going to get behind, you have to think about getting some potassium out there, whether it’s through manure applications or commercial fertilizer,” he says.
Manure Does More
For dairy farms, manure is already part of the system. Oehmichen says it can do more than supply nutrients to the next crop. Used well, it can also help build organic matter and improve the soil.
“There was a 10-year study that was just released,” he says. “It compared a no-till system with covers versus a no-till system with covers and manure, and the one system that gained the most organic matter development was with manure applied.”
Oehmichen puts a lot of value on what manure can add to the soil.
“You could do all the no-till and all the cover cropping in the world, but nothing drives organic matter development like manure,” he says.
Organic matter helps soil hold water and nutrients while improving its structure. Commercial fertilizer can replace nutrients removed by a crop, but it doesn’t provide the same benefits for building organic matter.
“Anybody that got out of milking cows and got into cash cropping, that is something they miss every day,” Oehmichen says. “Commercial fertilizer does the trick, but it doesn’t do it on the organic matter side of things.”
Still, more manure isn’t always better. Oehmichen says soil biology can only process so much manure at one time, so application rates and timing matter.
“Ten thousand gallons is kind of your peak mark for what your biology can process,” he explains. “Even if you have the most robust ecosystem out there, there’s only so much the biome can process at any given time. The rest of the manure is going to sit there.”
When heavy applications sit on the soil through freeze-thaw cycles, some of those nutrients can move off the field through runoff. After putting the time and money into hauling and applying manure, Oehmichen says producers should do what they can to keep those nutrients where they belong.
“If you spend all this time and money applying manure and paying people to get that manure out there, why do you want it to leave the target?” he asks. “Why do you want that field to lose it?”
Give the Soil Something to Hold Onto
No-till, reduced tillage, low-disturbance manure application and cover crops all can help keep soil and nutrients in place.
“With conservation agriculture, it’s about protecting the soil from erosion,” Oehmichen says. “You can choose not to till that field. You can just do low injection or dribble barring. Or you can bring in cover crops to slow water down and hold everything there.”
Fall tillage can make a field look finished. Manure is incorporated, the stalks are worked in and the field is ready for winter.
But there’s another side to it.
“When those soil clods get disrupted, they lose their ability to hold themselves together,” he explains. “It’ll run off more like sediment, fine particles, which fill more nooks and crannies and increase compaction. That slows infiltration, and it increases the amount of sediment leaving the field. In that sediment, it carries all the fertility with it.”
Losing soil isn’t just about seeing a little dirt in the waterway.
It’s also losing the nutrients and organic matter producers have spent years building.
“A dime’s width of soil equates to 10 years of development of that soil,” Oehmichen says. “And it also equates to about a ton of soil per acre. You can see fields where it’s multiple times that, and that’s where all the fertility is running off.”
Rye, Wheat or Triticale?
Once the corn silage is gone, Oehmichen likes putting a winter cereal back on the field, especially where manure is going down or erosion has been a problem.
“The immediate next step would be to look at a winter cereal,” he says. “You want something with the aggressive growth of a small grain, but the robust ability to survive and stay green into spring.”
For most producers, he narrows the list to winter rye, winter wheat and winter triticale.
Winter rye
Rye is the tough one.
“Rye is nice because it’s cheap, it’s produced widely, and it has some of the best winter survivability of any winter grain,” Oehmichen says. “If it gets winter-killed, it had been a colossally bad winter.”
It also gets moving quickly in the spring. For farmers looking for some spring forage, rye can be chopped around late May while it is still nice and green.
“If somebody was looking at, ‘Maybe I do want to chop it,’ you’d be looking at around that late May timeframe,” he says. “It’s not a slouch. It provides a big benefit, and it grows nice, thick and green.”
The challenge is keeping up with it once spring growth takes off. Rye can become difficult to terminate once it gets past about 10 inches, and all that biomass can also tie up nitrogen as it breaks down.
“Once it gets past that 10-inch mark, other than chopping it, it is virtually unkillable,” he says. “The biomass production is incredible. People plant corn into it and the corn looks skimpy early on because the ecosystem in the soil is trying to break all that down. They need a lot of nitrogen to drive decomposition.”
- Strong winter survivability
- Fast spring growth
- Good option for spring forage
For producers planting corn into rye, termination timing and nitrogen management deserve some thought.
Winter wheat
Winter wheat is a little easier to manage.
“Winter wheat is nice because it’s manageable growth,” Oehmichen says. “It doesn’t get very tall. If you didn’t get to that window to terminate it, you’re not going to have a huge amount of biomass to deal with.”
For farmers looking for winter cover without a large spring forage crop, wheat can be a good fit.
- Manageable spring growth
- Easier termination
- Less biomass to handle
Winter triticale
Triticale gets Oehmichen’s vote when spring forage is the plan.
“Winter triticale is nice because it’s considered your pinnacle for a forage option,” he says. “If somebody’s like, ‘I want a cover crop, but I’d like to chop in the spring,’ that would be the first one.”
Triticale seed has become more affordable as production has grown, although winter survival can still be a concern.
- Good option for spring chopping
- More forage potential
- Can be less winter hardy than wheat or rye
“Triticale can sometimes not have the best winter survivability,” Oehmichen says. “Most of it will make it, but if we have a winter with late snow and freezing rain, it will suffer a little bit more than winter wheat or rye.”
Getting a Stand After Harvest
Picking the right seed is only part of getting a cover crop established. Oehmichen says how the seed gets into the soil can be just as important, especially when conditions are dry.
Broadcasting remains a popular option because it’s fast and doesn’t require another specialized piece of equipment. Farmers can cover a lot of acres without slowing down harvest too much.
“Broadcasting seed is by far the most utilized,” he says. “Makes sense. You can go faster, and access to equipment is easier. But it’s very weather dependent.”
Dry, crusted soil can make broadcasting a bigger challenge. Seed may germinate on the surface but struggle to push through the crust and establish a good stand.
“That crust on the soil surface is like asphalt,” Oehmichen says. “Asking a seed to not only germinate but punch through that hard crust, that’s a lot.”
No-till drilling can improve seed-to-soil contact and give the crop a better chance, even when the soil is dry.
“If you no-till drill, despite it being dry, that seed has seed-to-soil contact and a far greater chance of growing,” he says. “We broadcast seed a day or two prior to drilling in the same field, and it was only growing in the cracks. A lot of the seed was still sitting there begging for more rain.”
Oehmichen has also seen manure application help a broadcast cover crop get established. In one field, the difference was easy to see.
“Right to the line where that applicator stopped for the manure, that’s where the rye stopped growing,” he says. “That little bit of manure and soil disturbance was enough to jumpstart it.”
Look at More Than Cost
There’s no getting around the cost of a cover crop. Seed costs money, manure application costs money and another trip across the field adds up. So it’s fair for producers to ask what they’re getting in return.
Oehmichen says there is more research available now to help answer those questions, especially when it comes to erosion, nutrient availability and what cover crops can contribute to the next crop.
“Cover crops are able to do a lot of things, but a lot of it gets explained anecdotally and lost in the weeds in data,” he says. “But there’s more and more research, more trials, where you can see what kind of erosion reduction you get, what kind of nutrient availability you can expect.”
He recommends producers lean on the people and resources available to them, including agronomists, seed dealers, watershed groups, NRCS staff and university researchers. But some of the best information can come from simply walking the fields and seeing what is happening firsthand.
“Sometimes you just have to use some common sense,” he says. “Go walk your fields. Go look at what’s actually outside your door. Knowing what’s going on and being part of those discussions with your agronomists and seed salespeople makes a bigger impact in the long run.”
There can be benefits beyond what shows up on a soil test, too. A cover crop can help keep the soil in place and make a field more workable after wet weather.
“It is undeniable cover crops create stability on that field surface,” he says. “You can get on that field faster and get off that field faster. It is undeniable you have a reduction of surface runoff when you have something covering it.”
Oehmichen has also seen value in cover crops even when the stand doesn’t look like much. In one trial, berseem and crimson clover were planted late and only grew to about ankle height. At first, he wasn’t impressed.
“I even said, ‘This is crap. It’s not going to do anything,’” he recalls.
The numbers told a different story. The cover crop produced 800 to 1,000 pounds of dry matter per acre, which Oehmichen admits isn’t much compared with a strong cover crop stand. But the plants still contributed nitrogen for the following crop.
“It came back that it was like 800 to 1,000 pounds dry matter yield per acre,” he says. “That’s not very good in the cover crop world. But those little plants procured 60 to 90 credits of nitrogen still available in the spring.”
He could see the difference in the following corn crop, too. Areas where the cover crops had grown were greener, and the wheat residue broke down faster.
“Wherever the cover crops were, that corn is greener,” Oehmichen says. “It didn’t even matter if it was zero nitrogen all the way to higher rates. Wherever the cover crops were, the corn is greener, and there was less wheat stubble left behind because it got processed faster.”
Start With a Few Acres
Oehmichen doesn’t expect farmers to put a cover crop on every acre or completely change how they manage their soil in one season. He suggests starting where the need is greatest.
“If somebody’s like, ‘I don’t know where to start, just tell me what a normal start would be,’” he says, “pick those fields where you feel like you have major issues. The ones you know will wash out, the ones you know you want to hit with manure and you’re worried it’ll leave. Maximize your effort on those acres.”
From there, farmers can work through the basics.
- Pick a winter cereal suited to the field and the job.
- Give the seed good contact with the soil.
- Keep manure rates within what the soil can handle.
- Use no-till or reduced tillage where it makes sense.
“Those should be the fields you look at,” he says. “You don’t have to do everything, everywhere, all at once.”
The last load of corn silage may be headed to the bunker, but the work on those acres isn’t finished.
What happens after harvest can affect how the field handles manure, rain and snow through the winter and how it looks when the planter comes back next spring.
“When you create a mechanism that slows down the rate of erosion, that is also going to hold that manure in place,” Oehmichen says. “Manure is more important than you know.”
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