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Aerial applicators now hitting the ‘bull’s eye’

Originally published in the June 12, 2009, print edition.

By Dick Hagen
The Land Staff Writer

Getting 6-inch accuracy on spray patterns, applying as little as 1 gallon per acre of water-chemical mixture, achieving virtually total canopy coverage and doing this while flying 140 miles per hour only 10 to 15 feet above the ground is the proficiency of today’s aerial applicators.

“It’s very significant, the technology upgrades for aerial applicators the past few years,” said Vern Hofman, North Dakota State University Extension agricultural engineer conducting swath testing at the Hector airfield June 2.

“Because of pattern testing like we’re doing today, plus flow control systems built into their airplanes and of course the remarkable GPS guidance systems now being used by most applicators, the accuracy of today’s pilots couldn’t even have been imagined just a few years back,” Hofman said. And get this: drift complaints from aerial applicators have gone down in recent years, but complaints on ground rigs have gone up.

“Farmers today have big bucks tied up in every acre of crop. I think the aerial guys are much more conscientious about doing their very best to give their farmer customers the best job possible,” Hofman said.

He also indicated a shift now under way within the aerial industry with some pilots going away from herbicide work and more into fungicide and insecticide applications. “Later in the growing season, a lot of growers don’t like to see wheel tracks in their fields so aerial applicators then get called to the job. And on a cost per acre basis there really is very little difference between ground rigs and airplanes.”

A big reason for the increase in production efficiency of today’s aerial applicators is a technology 25 years in the making by engineers at Texas A&M University. Spectrum Electrostatic Spray Systems set up a magnetic field over the crop canopy with negative charged spray particles jettisoned from one side of the 60-foot boom beneath the plane’s wing, and positive charged particles from the opposite portion of the boom.

“The system is capable of up to 16,000 volts but typically we run at 8,000 volts and we change the voltage depending upon the chemical we are using,” said Ed Newberg of Newberg Sky Spray in Hector, and an early adopter of the SESS.

Now manufactured by a Houston, Texas, firm and being sold into agricultural areas worldwide, electrostatic applicators in South America are now down to a half-gallon per acre for Asian rust control in soybeans.

Spray droplets in this system are small, only about 50 microns, and are electro-statically charged in the nano-second out of the spray tip. Because the crop canopy has moisture, it acts much like a steel bar, instantly attracting both the positively and negatively charged droplets. This even happens on the underside of leaves, which explains why results with this electrostatic system are often exceptionally good. With certain fungicides such as Super Tin, Headline or Eminent on sugar beets, this system will penetrate the fungicide right down into the crown of the beet, almost impossible with any spray system.

Newberg said the electrostatic system is spendy going in, like about $38,000. But because of the tremendous reduction in spray volume (1 gallon per acre) and the proficiency of today’s ag airplanes, upwards of 2,500 acres per day are doable. “We’re talking a payback that first year for most applicators; some even just a couple weeks if you’re on a good run,” Newberg said, indicating these planes are capable of generating upwards of $2,000 gross per hour.

Keep in mind however, these turbine-powered Air Tractor ag planes powered by 680 to 750 horsepower Pratt & Whitney engines and with tank capacities of 400 gallons up to 800 gallons start at about $550,000. A well-trained, seasoned, professional operator is first priority to generate maximum opportunity in the competitive aerial application field.

As usual when comparing systems the proof is in the pudding. In 2008, University of Minnesota entomologist Ken Ostlie conducted soybean aphid spray tests with 2 ounces of Warrior used with 20-gallons of water per acre with a ground rig, 4 gallons per acre with conventional air and 1-gallon used with the electrostatic system.

One week after spraying, the control area had about 2,000 aphids per plant; both the conventional ground and air applications had about 350 to 400 aphids per plant, and the 1-gallon rate had only 10 aphids per plant. Yield was 42 bushels for untreated, 53 bushels for ground and conventional air, and 58 bushels with the electrostatic spray system.

By its very nature, piloting an ag plane is constantly demanding. Newberg said, “I say after a while it’s like riding a bicycle, but you’ve got to pay attention.” He’s now posting something over 15,000 hours of aerial application work.

Wind conditions obviously complicate aerial work. Herbicide work is questionable with winds over 10 mph, and fungicide work is OK with winds up to about 15 mph.

The $100 per airplane swath testing done June 2 at the Hector airport isn’t a requirement of being a licensed applicator. However, 14 pilots showed up and Hofman said that’s an indication of aerial applicators wanting to do their best for their customers.

Today good records on every field visited by an aerial applicator are a must. If that field is sprayed four times in a season, each visit needs to be recorded and available to the farmer if he needs “hard copy” verification of pesticide usage. An add-on piece of technology (costing about $28,000) called the M3 Satlock information system (a Microsoft product) is used by many applicators and provides precise application data plus direct guidance to each field. That’s why you no longer see “flag bearers” and white paper markers dropped at the ends of fields being aerially sprayed.

With soybean aphids generating “good money” for aerial applicators the past two years, is 2009 likely to be a repeat?

University of Minnesota specialists say an aphid infestation is likely again this year because of a relatively mild winter and the aphids now over-winter in buckthorn. Buckthorn is found everywhere in Minnesota windbreaks, fencelines. so come July we’ll know.

Minnesota currently has about 200 licensed aerial applicators, and that’s a number holding fairy steady despite the influx of big, ground rigs purchased by many cooperatives and individual farmers.

“There’ll always be a place for aerial applicators, partly because of the unpredictable nature of our weather which sometimes drops so much moisture ground rigs aren’t possible. Also the timing of various crop pests is sometimes a guessing game. Look what happened to soybean aphids the past couple years, both early and late explosions of this insect. When you literally need thousands of acres sprayed in just a few days, airplanes are a must,” Hofman said.

Current Environmental Protection Agency label language prevents 1-gallon per acre applications with many chemicals but as usage of the electrostatic system continues to increase, both chemical manufacturers and the EPA will likely be adjusting label language in the future. If the net result is both more efficiency for aerial applicators and even better results for growers, it’s a win-win situation for agriculture.

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