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Corn+Soybean Digest

Using Precision Ag to Save Time and Money on Your Corn and Soybean Farm

A 35-40% savings in nitrogen (N) applications is being seen by a Minnesota grower who uses remote-sensing tools in variable-rate application to help monitor residual soil nutrients.

That example from Gary Wagner, Crookston, MN, illustrates the huge benefits of using precision farming from one extreme or another. And with the cost of precision farming getting cheaper, there's another reason to use 21st century technology to boost production efficiency and ultimately — crop yields.

If you're not using some sort of precision ag to monitor yields, apply chemicals, plant more efficiently, drive the tractor straighter or simply stop a crick in your neck, you're likely increasing your input costs, says Matt Darr, Iowa State University (ISU) agricultural engineer.

“Precision guidance systems are popular because they're easy to use, are getting more inexpensive, improve efficiency, save time and labor and can be used for a variety of field work,” adds Marv Batte, Ohio State University agricultural economist. “The potential savings are numerous and immediate.”

Wagner farms multiple crops and was a variable-rate application (VRA) pioneer in the mid-1990s. “We had some prototypes of the Concord airseed systems in 1997,” he says. “We're still using a derivative of the same system. This year we will use a John Deere GS2 and an air-seeder cart. We can control three dry products and anhydrous ammonia at the same time.”

He rotates soybeans with spring wheat, sugar beets and edible beans. VRA with remote sensing enables him to measure the amount of nutrients provided by sugar-beet tops incorporated into the soil during harvest.

“Based on remote-sensing images, we're finding that 70% of available N stored in the sugar-beet tops (30-300 lbs.) becomes available for the next crop,” he says. “Our spring wheat N needs are 35-40% less. Growers coming back with corn should absolutely experience the same N savings.”

CHRIS WAYMIRE, Yellow Springs, OH, uses a Raven Envizio-controlled AccuBoom system to help eliminate skips and overlaps on his corn-soybean operation. His GPS-guided sprayer is an 80-ft.-wide BestWay Field-Pro III 1200 model. Spraying only zones that need various types of chemicals produces big savings, he says.

“My fields are not even, and a few are small with a lot of point rows,” says Waymire. “With this system, I can set boundaries for spraying by driving around the field. It draws out the boundaries on the unit's in-cab screen.”

The AccuBoom feature automatically turns boom sections on when he travels in areas of a field that have not been covered. It turns boom sections off when traveling over parts of the field that have already been sprayed. The system also uses GPS to read any no-spray zones in a field.

Overall, he saves 2-5%/acre on chemical applications. That's up to $3/acre saved, which easily covers the $2,500 additional cost of the AccuBoom. A GPS yield-mapping system tells him which soils produce the best yields, he says.

WAYMIRE ADDED A late-model tractor for 2009, a Challenger MT 665-B with auto-steer for planting. A new White model planter is equipped with Tru-Count air clutches that shut off when it gets to a zone that has already been planted.

ISU's Darr says even the simple savings seen in preventing overlap of tillage, spraying or other field operations can help the farmer's bottom line.

“A typical application would have an 8% overlap,” he says. “Even in a 50-60-acre field, that's one less pass over the field by the time you're done.

“A $1,000-1,500 lightbar can cut overlap to 4%. An auto-steer system will knock it down to 1-2%. And using RTK will put it at nearly zero.

“It's nearly impossible not to get your money back on a lightbar system with just a few applications,” Darr says. “You're saving fuel, time and labor in the field. If you're farming 2,000 acres, you're going to pay for even the highest input GPS. And if you hire spraying from the co-op or other source, your passes are going to be fewer and your costs should be less.”

DARR SAYS IT'S hard to pin down the cost savings of precision agriculture. “But it's a no-brainer that every farmer should at least own a lightbar for fertilizer or tillage applications on even a 300-acre operation,” he explains.

He says automatic swath control, in which GPS signals automatically turn spray nozzles or other components on and off, make equipment more efficient, as with Waymire and Wagner.

“A sprayer can automatically shut off and on much faster than we can as an operator,” says Darr. “That VRA technology has been widely growing the past year because of its direct economic benefit and simple integration into current sprayers.”

Getting fertilizer or other chemicals “in the right place” is among the main advantages Wagner sees in his operation. He says he doesn't see a lot of savings in total fertilizer applications, “but we're doing a better job of spreading it across the field.

“The fertilizer input cost is about the same. Our average fertilization across a field is probably 4-5 lbs. lower. But we are getting a better return on investment because it's applied where it needs to be,” Wagner says.


With precision agriculture now in its 16th year, more and more growers are using high-tech gadgets. If Ohio is any indication, well over half of commercial farmers are using precision farming equipment.

Ohio State University Ag Economist Marv Batte and his associates surveyed some 2,500 Ohio farmers to determine their use of some form of precision ag in 2007 (download the survey PDF at

Nearly 55% of commercial farmers had adopted at least one piece of precision-farming equipment. GPS guidance systems and yield monitors were the most frequently adopted, with about 32% of all commercial farmers using them through 2007.

“Since 1999, adoption rates jumped 27%,” says Batte. “Adoption rates of yield monitors increased 15% since 1999.”

He says most growers with precision guidance still use lightbars over RTK at a rate of 86% to 14%. Some 70% used a differential global positioning system (DGPS), compared to just over 2% using RTK. (One-fifth of those surveyed didn't know what type of GPS they used.)

Of the GPS systems farmers said they used, Trimble totaled 39%; John Deere, 14%; Raven (Starlink), 11%; Spraying Systems Co./Centerline/Midtech, 11%; Outback, 10%; Ag Leader, 4%; Autofarm, 3%; and 9% used other systems.

Batte says 92% of the growers using GPS used it for spraying/fertilizing, 35% for planting, 24% for tillage and 19% for combining.

Nearly 85% of the largest farmers have adopted at least one of the precision-agricultural component technologies. The average farmer adopted 4.5 precision-agriculture components and they are adopted in sets to get the most out of the equipment used.

“Highest net benefits were for VRA of lime and phosphorus and for precision-guidance technology,” says Batte, adding that over 50% of the farmers adopting precision ag say that benefits exceed costs.

VRA using aerial imagery is available from several companies, including InTime ( InTime Connections announced software that allows streaming of any RTK-correction data over a wireless phone, as well as simultaneous logging of positional data or logging of raw serial data and shows the latest weather radar image with the push of a button.

While RTK GPS systems are more common and lower in price, there are new gadgets to help control, monitor and service the systems. For example, Leica Geosystems' No DriftTM mojoRTK features a plug-and-play system that can help steer older steering systems.

Leica's Virtual Wrench is a wireless, Web-based remote service and diagnostics tool used via the cell data network. At the user's request, technicians can train, view screens, diagnose, update software and even press buttons remotely for the user.

The mini GAC moisture tester from DICKEY-john can test over 450 grains and products. It features USB (Universal Serial Bus) compatibility for calibration loading, automatic temperature compensation, runs off a 9-volt battery and can fit on your belt.

On a larger scale, John Deere has a new sensing system on corn heads, AutoTrac RowSense. It works by integrating GPS data from the StarFire Receiver with mechanical feeler data from new row sensors located on the corn head.

Other new precision-ag gadgets fit under the telematics umbrella, which operate similar to the OnStar system in many vehicles. For more information, go to

Matt Darr, Iowa State University ag engineer, notes that “what really jumps out on Batte's data is if it's automated, it lets us be more productive and get more done. VRA hasn't taken off like guidance systems have, butit can be very valuable.”

He says GPS receivers are the core components, “and GPS accuracy will continue to be the limiting factor in the performance of machinery automation systems.

“Low-accuracy GPS receivers will lead to poor performance of auto-steering systems and disappointing results of auto-swath systems for sprayers and planters.” He adds that as the costs of inputs continues to rise, “the payback period for higher-accuracy GPS receivers is reduced.”

More RTK network providers are becoming available. In Iowa, for example, Darr says the Iowa Department of Transportation has an RTK network, IaRTN, with 78 base stations (see

He says special receivers connect to the base stations through cellular modems. Several companies have the receivers available, he adds.

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