Keys to Sunflower Quality
Tuesday, August 1, 2000
filed under: Harvest/Storage
Following the right steps from preharvest to postharvest helps maximize yield and quality potential.
Mike Clemens would know. He has produced sunflower on his farm near
Wimbledon, N.D., since 1975. Clemens usually grows oil 'flowers, although he has grown some confections in the past, and half of his 2000 sunflower acreage is confection.
He switched his oilseed production to NuSun this year. "That's where the
industry is going," Clemens affirms. "Our product will have to get into the domestic market to get used up. I think it's very important to raise what the consumer wants."
Only once, in the early 1990s, has Clemens used a desiccant to dry his sunflower for harvest. He had a market opportunity for his oil sunflower that year, so he used the desiccant to speed drydown. But desiccants seem to need temperatures around 80 degrees for an application to be effective, Clemens says - and then there's the cost of the chemical and its application. So in most years, Clemens depends on frost to help dry
his sunflower for harvest.
"Usually, within seven days after a freeze, it's ready," the Barnes County producer indicates. "The magic date for us always seems to be around October 15 that we start harvesting." He starts taking sunflower at 18-19 percent moisture and tries to wind up harvest, weather permitting, within a two-week window.
Clemens realizes that the later the season, the greater the risk of weather-related problems. But he also notes that shatter losses from the combine header seem to be less at higher moistures, compared to harvesting standing sunflower at 12 or 13 percent.
"We usually try to dry seeds down to 12 percent, then put them in the bin and cool them down to 9-10 percent moisture. If we harvest at 12-13 percent moisture, we'll direct-bin them and use air to dry them down to below 10 percent," Clemens explains.
"For long-term storage, more than three months, you have to get sunflower to eight-percent moisture. If sunflower isn't stored adequately, they'll deteriorate from heat and
mold. Discounts alone will pay to have an aeration system put in. Air is the key to maintaining sunflower quality."
Clemens harvests confection sunflower at 15- to 16-percent moisture, using hull appearance as a key indicator for combining. "If the black stripe is rubbing off the seed when you're combining, it's too wet," he says.
He prefers to run his combine with the bottom sieve open at a higher wind speed - similar to settings for harvesting wheat - when harvesting sunflower. "The advantage is that it seems to blow more of the fines out, with less plugging and a cleaner sample," Clemens relates. "You'll take in more sticks; but the fines in sunflower weigh more and can even be more of a dockage problem than sticks."
Rather than haul his crop to the elevator at harvest, Clemens prefers to store both better-quality and poorer-quality 'flowers on his farm, in anticipation of higher premiums and lower discounts in the off-season.
Sunflower requires a bit more management after harvest than other crops. Clemens says seeds can "heat up fairly fast" if seed moisture is above 10 percent and they're not aerated, so bins need to be checked regularly. And "good housekeeping" is a must.
"You [need] to keep a clean work a rea, and blow the combine and grain dryer setup with an air hose daily," he advises. "If dust forms, get it brushed off to eliminate the chance of fire, which is even greater when conditions and the crop are drier."
Clemens points to his own neigh borhood as evidence that combine fires at sunflower harvest are not to be taken lightly. He knows of four combines totaled by fire within a 50-mile radius of his farm during the 1999 harvest.
It's a good practice to keep a small pressure sprayer filled with water on hand in the combine in case of fire, Clemens adds, pointing out that a $25 fire extinguisher is a good investment if it can prevent the destruction of a $140,000 combine - not to mention insurance policy premium increases. - Tracy Sayler