For many dairies, corn silage harvest wraps up a long growing season and kicks off a busy stretch of manure hauling. For crop and forage consultant Brendon Blank, it also opens the best window to grow something useful after the chopper leaves — forage for the bunk, cover for the field and activity below the soil surface.
“The sooner you can get a cover crop in after corn silage harvest, the better,” Blank says. “One of the goals of any crop you’re growing is to collect as much free stuff as possible — sunlight and CO₂ and all those things plants grab to turn into organic matter through photosynthesis.”
Blank wants fields capturing sunlight for as much of the year as possible. Every day the ground sits bare is a missed opportunity to grow forage, protect the soil and feed the biology below the surface.
“You don’t want to waste any of the energy you can collect,” he says. “You want your field to be a solar panel as much as possible, collecting sunlight and turning it into energy fixed in the soil.”
Why Silage Acres Fit
Corn silage leaves less residue than grain corn because most of the plant is hauled off for feed. Since silage also comes off earlier, those acres still have fall growing days left for a cover crop to take up nutrients and shield the soil before winter.
“You’ve got a lot of growing season left after the corn silage comes off,” Blank says. “Don’t waste those days. Don’t waste the sunlight.”
Beyond capturing sunlight and nutrients, cover crops can shield fields that are left exposed after silage harvest.
“You’ve got zero residue on the field, so the field is very vulnerable to erosion,” Blank explains. “Bare soil can erode from both water and wind. It’s amazing how much wind erosion can take place in winter when everything is frozen, especially if things are dry.”
Corn does its best work in the heat of summer, then slows down as temperatures drop. Many cover crops planted after corn silage are built for those cooler months, so they keep growing during a stretch when corn cannot do much. This is why the fall window after silage harvest can still be productive instead of sitting idle.
“Corn grows really well from June 1 to September 1,” he says. “Cover crops grow really well in September, October, November, March and April. Corn has to be above 50 degrees to do anything. Some cover crops, if you sow them at 32 degrees, are working.”
He also likes how solid-seeded covers fill the gaps left by row crops.
“With row crops, you’re planting every 30 inches,” he explains. “Having a solid-seeded cover growing between those rows puts a lot of roots out there, grows soil biology, pumps sugar into the root zone and mellows the surface.”
Manure First or Cover First?
For many dairies, manure follows corn silage almost immediately. Blank urges producers to think through the order.
“I really like to plant the cover crop first,” he says. “You can put your manure over the top later.”
He is a strong advocate for applying nutrients onto something green and hungry. A growing crop is ready to use nutrients as soon as they arrive.
“I’d rather have a plant waiting for the manure than manure sitting there waiting for a plant,” Blank says.
Late-fall timing adds another challenge. If manure goes first, wet ground can delay planting until the cover crop has little time left to grow.
“If you’re putting down 15,000 gallons of manure and you don’t have a cover crop planted, you’ve got to wait for the ground to dry out,” he says. “A lot of times you’re getting into October, and getting the cover planted may be difficult or too late to do much good.”
When covers are already established, farms often gain more flexibility. Low-disturbance injectors, dribble bars and drum rollers have all worked in systems Blank has seen.
“I’ve seen low-disturbance injection into forage triticale work,” he notes. “I’ve also seen guys come back with a big drum land roller to push everything smooth. It’s almost like you transplanted the plants. You push them back into the ground, and they do fine.”
Choosing Species and Rates
Blank spends a lot of time on species selection, especially for silage ground receiving manure. Triticale tops his list for winter forage. Ahead of corn, cereal rye is still a strong option, but it needs management.
“Cereal rye is a great cover crop,” he says. “Not exactly the right cover ahead of corn unless you manage it on purpose. If you’re planting corn into cereal rye, it has to be killed at planting or before, and you’ve got to band nitrogen with the planter — ideally about 40 units.”
With manure and favorable fall weather, rye can grow fast and thick.
“You can get so much growth on rye it can be problematic in spring,” he warns. “Even if it doesn’t get tall, it can get out of hand fairly quickly.”
He feels many growers seed heavier than needed on silage acres, especially with manure.
“If you can get it planted in the first half of September, and you’re going to do just cereal rye, 20 pounds is adequate,” he says. “The later you go, the more seed you need, but for early planting 20 pounds is enough.”
He often balances a lower rye rate with fast-growing species that winterkill, including oats, barley, flax, phacelia or radishes.
Those species help manage nutrients and spring workload. They take up manure nutrients in fall, die over winter and begin releasing fertility before corn needs a big pull.
“Those crops die in winter, and their roots start decomposing in fall and early spring,” he says. “Now you’ve got nutrients being released when you plant corn and corn is little.”
If everything is rye, nutrient release can come in a rush several weeks after termination.
“Cereal rye does a phenomenal job of sucking up every available bit of fertility, but then it holds onto it for a while,” Blank explains. “If I can have something die in winter, I’m spreading nutrient release over a much longer period.”
He compares the idea to feeding cows. A ration works best when the rumen stays steady, not when nutrients arrive in one slug. A cover crop mix can do something similar for the next crop by spreading nutrient release across time.
On heavily manured ground, he usually skips legumes in this window.
“I want to keep this mix economical,” he says. “Legumes are some of the most expensive cover crop seeds. If I’m putting down manure, especially with a short growing season, I’m more interested in absorbing the nutrients already there than growing additional nitrogen.”
Termination, Planters and Pitfalls
If rye is in the mix ahead of corn, Blank wants planters and sprayers ready before spring. He sees three common problems: too much seed, poor termination timing and planters not set for cover crops.
“Your corn planter has to be dialed in to plant into it properly,” he says. “You need the seed deep enough — I like 2.5 inches — good row cleaners and good closing wheels. Banding nitrogen really helps.”
On termination, his rule is simple: either kill it early enough for it to be dead and dry, or plant while it is still very much alive.
“I either want it totally dead — sprayed 10 days to two weeks prior, where it’s brown and crispy — or I want it very much alive,” he says. “By very much alive, I mean sprayed just a day or two ahead of planting, or a couple days after.”
The trouble comes in the middle, when rye is half-dead and rain keeps the planter out.
“If it gets to be eight or 10 inches tall, you spray it, and then it rains and you can’t plant for a week, the cover crop lays in a mat on the soil,” he warns. “The soil doesn’t dry out underneath.”
He urges growers to watch the forecast and avoid spraying rye right before a wet stretch if the planter will not be able to follow.
The Payoff: Fertility, Water and Soil Life
Blank views cover crops as both protection and a long-term investment in soil function.
“They really help capture and hold onto nutrients from manure application,” he says. “You reduce runoff and leaching, especially nitrate moving deep into soil and drain tiles.”
Beyond loss prevention, he ties cover crops to a more active soil ecosystem.
“Every plant puts out enzymes through root exudates to break minerals loose from the soil and turn them into a plant-available form,” Blank explains. “We’re pumping sugar into the soil, and the sugar feeds microorganisms that break nutrients loose.”
He does not want soil treated as a passive sponge.
“I want the soil on your farm to work for you,” he says. “Your soil is teeming with life. A lot of those organisms break nutrients loose and make them plant-available. The more of those organisms we have, the more miners you’ve got working down in the soil.”
Blank compares soil biology to the rumen. Feed keeps rumen microbes active, while cover crops provide food for soil microbes that can improve fertility, structure and water movement. Roots and residue create pore space, improve aggregation and keep oxygen and water moving through the profile.
“Everything in the soil has to eat and breathe,” Blank adds. “Cover crops create food for the microbiome, but they also create habitat.”
He also wants roots near the surface, right where the planter will place seed.
“Too often we focus on deep-busting radishes,” he says. “Those are useful, but it’s also vital to have roots near the surface where seed is getting started. A solid-seeded cover can really enhance that zone.”
From Corn Silage to Winter Forage
Blank has watched more dairies move beyond planting a cover crop just for soil protection and into a true double-crop system: corn silage followed by a winter forage such as triticale.
“I’ve seen the chopper and the drill in the field at once,” he says. “One farm hires a guy from off the farm and they get triticale in the ground as fast as possible to pull more yield the next spring.”
A few days can change the crop’s value. Blank says a 10-day shift in the planting window can mean a 20% to 30% yield difference.
He points out how farmers will run corn planters all night in spring yet may not show the same urgency with fall forages.
“I think it’s more valuable to do it with winter triticale than even corn in spring,” he says. “Your daylight hours and heat units are shrinking very rapidly. More fall growth increases spring yield and can let you harvest a little earlier.”
For triticale after silage, Blank likes to plan months ahead. It starts with corn hybrid selection, expected harvest date and labor. Can someone plant while corn silage is coming off, or does the farm need to finish chopping before the drill moves?
On farms chopping 100 acres of silage but planting only 50 acres of triticale, he may flip the normal sequence. Plant the short-maturity corn first, chop it first, plant triticale on those acres, then finish with later-maturity silage corn.
“It seems backwards to plant the short maturity first,” Blank says, “but it’s one of the tools that makes the double-cropping system work.”
In Wisconsin and similar climates, well-managed triticale can fit between corn silage and alfalfa in a ration.
“I’ve seen quality with milk-per-ton numbers real close to corn silage in spring,” he says. “You can hit fiber digestibilities of BMR corn silage or better, and protein numbers in the upper teens. It lands right between corn silage and alfalfa.”
The opportunity is real, he stresses, but management has to match the goal. “Having a plan ahead of time is the most important part,” Blank says.
Bringing It Back to the Farm
For dairies weighing whether to push harder on cover crops after silage, Blank boils it down to timing, planning and field selection.
“Have a game plan going into it,” he says. “Start in the fall when you’re ordering seed corn. Think about where corn is going next year, what’s well drained, what will let you get in and harvest if you decide to double crop. Then match your cover mix and manure plan to those fields.”
With the right forage choice, seeding rate, manure timing and termination plan, corn silage acres can feed cows, protect soil and set up the next crop before winter settles in.
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