I learned something new today: sunflowers can cause your tractor to catch fire!
What started as a day of planting into sunflower stubble quickly turned into a disaster as Charlie Edlinger’s new tractor went up in flames in a matter of minutes from the dry stalks.
“I immediately was trying the best I could to reach in and grab and pull stalks out and after 20 seconds I knew it was kind of a lost cause. So, I basically hopped back in the tractor real quick, got on the phone with my brother said ‘call the fire department ASAP,’” said Edlinger. “I basically had to turn it to this area with low residue here and face it into the wind and air it downwind so we could salvage the air seeder because I knew at that point the fire was going to take the whole tractor” [Ariana Schumacher, “Scorched by Sunflowers,” KELO-TV, 2022.10.21].
SDSU, naturally, has researched this problem and found oily sunflower residue can ignite at lower temperatures than dust from other crops:
To analyze the problem, master’s student Joseph Polin, now a doctoral student at Iowa State, and assistant professor Zhengrong Gu found that sunflower debris ignites at temperatures that are 68 to 86 degrees Fahrenheit lower than corn or soybean residue. In addition, the researchers discovered that a large part of the debris sticking to the combine was the white pith, which is then drawn into the fan that pulls air through the radiator to cool the engine.
“A portion of this dust ignites when it hits the turbocharger and exhaust system,” [professor Dan] Humburg said. “Once a fire starts, it’s easy for a spark to be relocated.” Many machine components—fiberglass shields, wiring harnesses, flexible hoses and plastic fuel tanks—can burn.
A greater engine load also increases the exhaust system’s temperature and the likelihood of fires, Humburg noted. Sunflower producers reported monitoring fuel usage and rated engine load to identify the point at which they will experience combine fires immediately [“Preventing Sunflower Fires,” SDSU: Connect, Summer 2014].
Edlinger says newer tractors may have greater risk of sunflower fire due to additional safety features:
“Sunflowers are a riskier crop for fires. This newer equipment has a lot more protective shields around the engines in the tractors. So, unfortunately, a lot of this protective shielding can trap residue and kindling you might say and it makes it harder for the residue to fall out so it contains the residue and keeps it trapped within the engine area,” said Edlinger [Schumacher, 2022.10.21].
Avoiding sunflower fires requires running tractor engines at slower speeds and pausing to blow the sunflower dust off the machinery, both of which cost producers valuable harvest time. Now-retired Professor Humburg’s research led him to develop a mechanical solution to further reduce fire risk:
On the kits, an enclosure is used to box in the hot exhaust components, and a pressure blower pulls a stream of air through a filter to remove all of the white dust.
“The clean air is pumped by the blower into the enclosure around the exhaust system, and the clean air flow into the enclosure keeps the dusty air from being able to get near the hot parts,” Humburg said.
DSH’s system is directed at the exhaust system.
“It will not prevent fires that originate at hot bearings, or electrical system problems,” he said. “I always advise producers to remain vigilant for possible fires from these sources” [Sue Roesler, “Humburg Develops Combine Kits to Prevent Sunflower Harvest Fires,” Farm & Ranch Guide].