Optimizing the Quality of Your Confection Crop
Several years ago, a set of trade standards were developed for nonoil sunflower kernels. These standards stipulate there should be no more than 10 percent broken kernels; not more than 0.5 percent heat damage; and not more than two percent insect damage. They also specify that kernels should be “free of strong, stale, flat or rancid flavors and off odors; be off-white or gray color; and have negative values for aflatoxin, E. coli and other pathogens.”
Working against the attainment of those standards are such villains as seed-feeding insects (e.g., seed weevil and head moth); premature killing frosts; certain weeds (particularly cocklebur); diseases (e.g., head rot); excess moisture and heat during storage; and various other factors which can — alone or in combination — add up to an unpleasant fact of life for producers: discounts.
While the relative importance of specific production-related discount factors varies from year to year, grower to grower and processor to processor, confection sunflower companies point to several prominent ones:
• Late Planting — This isn’t a widespread problem, but every year some growers tend to “push the envelope” on planting dates. And, if a processor needs additional acreage, he may accommodate them. The danger, of course, is the possibility of frost before a late-planted field has achieved physiological maturity. Along with reducing test weight and yield, that can result in discolored kernels, leading to significantly higher discounts or rejection.
• Insects — Economic populations of seed feeders such as the red and gray seed weevils, head moth and banded sunflower moth can inflict very serious damage if not controlled. But they commonly consume just a portion of the kernel, so those seeds often are not separated from other seeds during combining. “It’s very difficult to remove all insect damage from in-shell sunflower,” affirms Jim Krogh, president of Agway, Inc., of Grandin, N.D. “Yet it’s also difficult to explain to today’s consumer why there’s a hole in the seed they bought. The hole is unsightly; the kernel tastes bad. It’s a bad deal all around.”
John Donnelly, vice president-trading and purchasing for Red River Commodities, says his firm recommends confection growers be monitoring for these insects when a field is just beginning to bloom (five to 10 percent of plants). Since it is an edible product, economic thresholds for confection ’flowers are much lower than for oil-types. One to two weevils per plant should trigger prompt insecticide treatment, based on current recommendations.
• Cocklebur — This weed is a threat to confection producers not only on the basis of reduced yields, but also because its seeds are so similar to sunflower in size, shape and weight. That fact complicates separation during harvesting and processing and, if carried far enough, can result in a very displeased consumer.
Of the herbicides presently labeled for use in sunflower, none are effective at controlling cocklebur. So managing this weed currently comes down to (1) planting, if possible, on a field with no recent history of cocklebur problems; and/or (2) applying a postemergence shielded-spray treatment of Roundup (in those states where this use is labeled on sunflower); and/or (3) cultivation.
If cocklebur are present at harvest, confection companies recommend setting the combine header high enough to pass above the weeds without (hopefully) missing very many sunflower heads.
Ernie Taus, confection field production manager for Dahlgren & Company, says his firm once surveyed those producers who delivered cocklebur-contaminated loads as to what type of header they had on their combines. About 90 percent of those surveyed reported using an all-crop header, meaning they were cutting lower, thereby taking in the cocklebur along with hanging sunflower heads and stalk materials.
If the cocklebur infestation is limited to certain defined areas (e.g., field perimeters), Red River’s John Donnelly suggests growers harvest those areas separately and take care not to blend those seeds in with noninfested loads.
• Disease — This often is a factor out of the grower’s control, particularly with something like Sclerotinia head rot. In a wet year, the airborne Sclerotinia fungus can blow into a previously noninfected sunflower field to infect and rot heads, thereby producing large quantities of sclerotia. Some of the hard, dark sclerotia bodies may end up on the soil; but many others will find their way into the combine hopper. Sunflower should not be planted next to a field infected with Sclerotinia the previous year.
• Admixture — Dahlgren’s Ernie Taus says admixture has become an increasing problem in Upper Midwest confection sunflower, given recent years’ expansion of corn and soybean acreage in the region. Controlling volunteers is part of the answer; but perhaps even more important, Taus says, is for growers to do a good job of housekeeping in their combines, grain dryers, grain augers and storage facilities, making sure any leftover corn or beans are cleaned out prior to sunflower harvest.
• Storage — Tim Mortensen, general director for Sigco Sun Products, says the majority of dark nutmeats in confection sunflower being delivered by growers to his firm do not result from in-field influences. Rather, he suggests, they can be traced to inadequate drying and/or storage practices.
The maximum recommended moisture content for storage (with aeration) of confection sunflower is 11 percent for short-term (less than six months) and 10 percent for long-term (more than six months) storage. Storing seeds at 12 to 13 percent moisture and expecting a natural air drying system to bring them down to the correct level may not be feasible — particularly under late October/early November conditions in North Dakota/northwestern Minnesota, Mortensen says. “Generally, I think they need to look at artificial drying and then binning,” he observes.
Along with putting the seeds into the bin at the proper moisture, growers need to be monitoring the binned crop on a regular basis over winter — and particularly as warmer weather approaches, Mortensen emphasizes. Warm spots or crusted peaks can occur when the outside of a bin cools down, the cool air sinks and pushes warmer air and moisture up through the middle of the seed mass. Not correcting the problem is almost certain to fuel seed oxidization — and economic losses.
Spring is the time of year when the consequences of inadequate storage really show up, says Agway’s Jim Krogh: moldy seeds and/or kernel discoloration. For in-shells, it’s almost impossible to separate out the inferior seeds — until the consumer tastes them. “With the kernels, if they’re dark enough, you can get them out [with electronic color sorters],” Krogh notes. “But some are more of a light-roast color — and if you do actually roast them, they turn dark.” — Don Lilleboe
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