Article Archives
Fall Prep for 'Flowers? You Bet!

Thursday, August 22, 2013
filed under: Fertility

In today’s world, most sunflower in both the Northern Plains and the Southern Great Plains is produced under either a no-till or minimum-till regimen. The 2012 National Sunflower Association crop survey found, for instance, that among surveyed fields in Nebraska, Kansas and Colorado, virtually every one fell within either of those two categories. In South Dakota, more than 85% of last year’s surveyed fields were no-till, with another 10+% being minimum-till. The North Dakota numbers were 48% and 39%, respectively.

Minnesota is the glaring anomaly within this group. About 90% of the Gopher State’s sunflower fields in last year’s crop survey were tagged as “conventional.” That’s not surprising, given the typically higher-rainfall environment in Minnesota’s sunflower districts and the historically greater percentage of row-crop acreage there.

Kevin Capistran is among that conventional “super majority.” The current president of the National Sunflower Association farms east of Crookston, in northwestern Minnesota’s Polk County. His crop rotation encompasses sunflower, sugarbeets, wheat, barley, soybeans and corn under a mostly conventional-till system. A good chunk of his time also goes into operating Capistran Seed Company, founded by his father, Wayne (who still serves as its president).

Being a conventional producer translates into more fall ground preparation work — tillage, fertilizer and herbicide — for upcoming sunflower and other row-crop fields on the Capistran farm. The benefits to fall preparation of the next year’s fields are well-understood across northwestern Minnesota and adjacent parts of North Dakota — a primary one being that jump start when winter finally gives way to spring. “The way I look at it is, you want to hit the field in the spring with a light tillage pass, plant — and be done,” Capistran affirms. “The last thing I want to be doing prior to planting is to make ‘one pass for this, one pass for that and a third pass for this.’ It just takes a lot more time than I want to expend in the spring.”

The flip side, of course, is that adding more field preparation passes to one’s northern Minnesota fall workload can be challenging — especially if Mother Nature doesn’t cooperate with favorable weather on the heels of the busy row-crop harvest season. A late harvest and/or wet fall and/or early freeze obviously can throw a big wrench into one’s plans. “But if you get a lousy fall and it doesn’t happen, well, so be it,” Capistran responds. “You’re just back to where a lot of people start anyway.”

Capistran sunflower fields traditionally have followed wheat or barley through the years. “We typically know our history of P and K, so I don’t need a soil test to determine whether a certain field is going to need those nutrients,” he relates. “But on sandier ground, if we do need high loads of K, we’ll spread it on the grain stubble before it’s worked because that K is not going anywhere.” Any phosphorus requirements usually go on in the spring with the planter.

Anhydrous ammonia is Capistran’s preferred nitrogen source because of its per-unit cost. “And it’s the most stable going down in the fall. Typically we’ll be putting down between 50 to 70 lbs of N after October 15,” he says. Should a field going into sunflower the next spring test high in residual N, he’ll opt out of the fall application altogether. “If we need only 20 or 30 lbs, sidedressing is a good option.”

In a “normal” fall, Capistran usually has about a three-week window after the conclusion of the row-crop harvest to accomplish his ground preparation tasks. “The biggest problem I’ve had is waiting too long to put down my fall preplant herbicide (Treflan™EC for sunflower). Freezing temperatures and a liquid system don’t always play well together,” he quips. “Generally, it will be later in October when we put the preplants down because I worry about their longevity. I’ve never had a problem with Treflan breaking down too fast when I go fall applied, but there are certain other herbicides that don’t work well in the fall.”

While many sunflower growers utilize Spartan for weed control, the presence of sugarbeets in the Capistran rotation omits that option. “The Treflan is cheap and easy to use,” he says. “We typically plant Clearfield® or ExpressSun® varieties, so after the fall Treflan and seeding in the spring, we come back with the post-emerge mix — and we’ve had the weed control we need.”

Lighter soils obviously are not a good fit for a fall nitrogen application, especially ahead of a shallower-rooted crop, due to likely N leaching. “The practice doesn’t lend itself well to every crop or to every soil type,” Capistran affirms. “But in our soils, the nitrogen is not going to go deep beyond what sunflower — or sugarbeets — can reach. We’re not going to ‘outrun’ it.”

Dave Franzen, soil fertility specialist at North Dakota State University in Fargo, underscores that point about fall N treatment on lighter ground. “Sandy loam, loamy sands, sands — none of those lend themselves to the fall application of ammonia, urea or any other nitrogen product,” Franzen states. “Those soils don’t have the capacity to hold even ammonia, let alone nitrate.”

Franzen, who estimates that around 20-25% of North Dakota sunflower acreage receives a fall fertilizer application, knows late autumn in the Upper Midwest can be an “iffy” time. “But we never want to put any fall nitrogen on before the first of October; sometimes it can be the 15th. It would be that date where the soil temperature, measured at the four-inch depth between 6:00 and 8:00 in the morning, reaches 50 degrees.

“Then we want them to wait one more week before they’re putting out banded urea — which is a fairly common practice, especially West River (those areas west of the Missouri River) in North Dakota. Then it should be another week beyond that for broadcast urea.”

How much nitrogen will go on this fall compared to recent years? On the “less” side, it was a late spring and planting season across northern North Dakota and northwestern Minnesota, so harvesting of row crops is going to lag as well. On the “more” side, there’s the current price of anhydrous: around $300 less per ton than a year ago, Franzen notes.

For Minnesotan Kevin Capistran, committing a big chunk of his fertilizer dollars in the fall is not a deterrent. “I look at it as a hedge,” he says. “If you want some price protection, a lot of times you can get a price on anhydrous in the fall — but you usually can’t lock in the price for spring at that point. If the price is too high in the fall, well, maybe that’s a reason to wait and see. But often your fall pricing is better than the spring. So it spreads out our price risk.”

Both Capistran and NDSU’s Franzen say that one big reason why there’s not more fall ground prep for sunflower in conventional tillage areas is that many growers tend to hold off a final commitment on their sunflower acreage until winter or even early spring, depending on crop prices and early spring weather. Capistran admits that if he puts down nitrogen and Treflan in the fall on a given field, he has essentially locked in that field to sunflower. “But our rotation is pretty ‘locked’ anyway,” he states. “When we do decision making in the fall for a field that could be either soybeans or sunflower, we ask ourselves, ‘How dry is it?’ If on the drier side, we favor planting sunflower there.

“Then the other question is, ‘How much residual N is left after the wheat crop?’ Last year a couple of our wheat fields essentially burned up, and there remained 70 lbs of residual N. I don’t fertilize much higher than 100 lbs for sunflower, so it was a ‘no-brainer’ to go with sunflower on that ground.”

— Don Lilleboe

return to top of page

   More about Sunflower ►