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“Air is Key”

Saturday, September 15, 2007
filed under: Harvest/Storage

Mike Clemens grows both sunflower and corn. He’s a stickler for harvest preplanning, and looks to be even more so this year, because he knows what’s coming – a lot of bushels of late season crops coming off the field in a hurry.

“With the size of the crops that look to be coming in, we’ll need to be ready to throw the switch,” says the Wimbledon, N.D. farmer.

That means bins prepared, aeration and drying equipment lined up and in working order, and contingency temporary storage planned – Clemens will choose a spot to dump grain outside if it’s needed, mow down the site so he doesn’t have to contend with grass and weeds around it later, and put aeration tubing in place if grain needs to be piled.

“I think a lot of preplanning is going to be needed this year. Things will need to be ready to go instead of trying to call a dealer and find where tubes are at, and having him say they’re out and won’t be coming in for another three weeks,” says Clemens.

NDSU Extension Engineer Ken Hellevang agrees. “Because of the expected increased in corn production, there could be more demand for drying and storage capacity at the elevator, so farmers should plan accordingly,” he says.

Air is the key to keeping sunflower in good condition, Clemens stresses. “If you pile 13% moisture sunflower without aeration, it will start heating on you and within two weeks you’re going to have a heck of a mess.”

Helping the situation in temporary storage situations can be as simple as laying perforated aeration tubes down if you need to pile outside, he says. “I prefer 12” diameter tubing, they’re easy to handle and relatively economical to buy, and once you buy them you’d be surprised how you use them in other places for flat storage. We have a 75 ft by 140 ft long quonset style building, where in that situation I run two 12” tubes spaced about 30 ft apart if we pile in that building. We don’t necessarily put a fan on both tubes, we’ll do one tube for awhile and switch over to the other tube with the fan.”

Don’t forget a power source, and adequate power at that. “You want to make sure power is close if you’re piling outside so you can plug a 220 volt fan in, even if you need to string some electric cabling.

Managing the harvest of late-season crops can be challenging, and requires flexibility according to the weather, custom harvesting availability, and what crops and what fields are ready to be harvested.

Clemens prefers to harvest sunflower at about 12-13% moisture, than cool it with full floor fan aeration with at least 1 cfm (cubic feet of air per minute) per bushel. “Twelve to 13% is a nice moisture range to be working with. We’ve taken sunflower up to 18% moisture, but they have to be dried immediately.”

If you have to choose, harvest sunflower on the nice sunny days, and corn on the damp, less than optimal weather, he advises.

“That last week of October and first week of November really gets to be a crucial time, so you really need to watch your weather and decide what you’re going to take,” Clemens says. I’d say take your sunflower, and leave your corn, because you can always go and get the corn on a lousier day.

“Sunflowers just won’t feed in well when they’re damp and raggy, but I’ve harvested corn when it’s raining out,” he continues. “Corn has that husk on there and sheds the water. And also on the combine setting, I can turn the fan up on my Case IH combine to 1,250 rpm, so on corn you can keep your sieves clean even when it’s pretty damp out, where with sunflower if you did that, you’d blow’em out the back end.”

Postharvest planning starts before planting

Ward Eichhorst knows a little something about sunflower aeration and storage – “Resistance of Sunflower to Airflow” was his master thesis in ag engineering at NDSU in the ‘80s.

Now he combines that knowledge with experience, farming with his father-in-law Donald Paulson near Coleharbor, N.D. He has included both oil and confection sunflower in his crop rotation.

“I think there’s a lot of things that relate to harvestability before you even put sunflower into the row crop planter or air seeder,” he says. For instance, selecting a hybrid that has good drydown characteristics, weed control, and a uniform stand. “If you can get that combine out there at 11-13% moisture where you can do a good job of cleaning them up, and you get a few nice days of natural air drying in the fall, you won’t have troubles getting them down to 10% moisture for delivery.”

Eichhorst usually plants an early variety, so he can take sunflower off the field earlier in the fall. “I want to take advantage of nice days in October. When the calendar rolls into November, you just don’t get enough warmth in a day to do effective natural air drying. You can do some decent drying with 30s and 40% humidity, but at 70 and 80% humidity, you’re just burning up electricity.”

Storing sunflower is no more difficult than handling any other crop. “It’s a relatively easy crop to store. You just have to manage the fact that it’s an oil crop, like canola and flax, which can deteriorate faster than a protein crop like wheat or soybeans,” Eichhorst says. “You get a little bit of water in a bin of corn, because of the starches and enzymes that break down, corn can probably deteriorate faster than any of them if not managed properly, in my opinion.”

Eichhorst finds confections easier to manage postharvest than oil sunflower. “Oils are a little more temperamental. If moisture is an issue, oils will go bad worse than a confection will,” he says. “With confections, you have a larger, lighter seed – 24 or 25 lb test weight versus oil at 31 to 32 lbs. So there’s less density making it easier to push air through a confection bin compared to an oil one.”

Using a Kwik Kleen or similar precleaning equipment to remove dockage and foreign material before storage would help air go through a sunflower pile easier, he suggests.

Like Clemens, Eichhorst usually aerates sunflower with at least 1 cfm/bu. in a circular steel bin, and will use perforated aeration tubes down the center of sunflower stored flat on a concrete floor of a livestock confinement barn.

He’s used aeration tubing placed vertically as well as horizontally. “We’ve even used 4” diameter tubes about 5 to 6 ft long with a fan at the top running off 110 electricity. If we think we have a spot that could present a problem, we thread a fan onto a tube, and you want to get that perforated tube down into about three or four ft of the grain to draw moisture out of the crop.

“I’ve had three of those on an almost 300,000 lb pile, equivalent to about 10,000 bu. in a confinement barn, and we were able to keep that crop in condition,” Eichhorst continues. “We had two at the ends and one at the center of the pile and we had them running from the day we put the pile in until the day we took it out. They help maintain the crop and work well for temporary barns and annexes.”

Lee Bonn, sales manager for storage manufacturer Westeel in Fargo, cautions that aeration tubes are appropriate to help maintain grain condition in temporary and flat storage situations, not for larger, circular bins. “In a 35,000 to 75,000 bushel bin, you cannot get enough cfm through a round tube to do adequate drying in a bin of that size,” he says. In today’s large contemporary storage facilities, the key to aeration is to do the system right from the start.

“When people are looking to put up bins, we’ll ask ‘what’s the product you want to store, and what’s the starting moisture of the product you’re putting in the bin. That’ll help us determine the system we need.”

Bonn suggests that a good online source to browse for grain storage manufacturers and products is – the online version of the 2007 Equipment Catalog is a comprehensive searchable database of over 200 suppliers spotlighting over 80 product/service categories. – Tracy Sayler

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