Precision ups yields, lowers N rates

Technology can be great when it saves money and places inputs precisely. Eric Fuchtman of Creighton and his father, Clifford, have integrated technology into their cropping system, utilizing 20 years of soil test results for nitrates to vary the rate of anhydrous ammonia fertilizer applied over the 1,000 acres of corn they raise.

At a glance

• Father-son duo uses variable-rate technology, GPS and grid sampling.

• Corn yielded 200 bushels, with 100 pounds per acre of N.

• In 2009, they advanced to automatic rate switching.


Eric Fuchtman says that the system they use now is the fruition of years of tinkering, as well as waiting for technology to catch up to their ideas. “We’ve been using anhydrous ammonia for years. We usually apply in mid-April, a few days before disking and planting,” he says.

Exactly where they want it

“Anhydrous kind of gets a bad name,” he continues. “But the way we are using it, the nitrogen gets exactly where I want it.”

Fuchtman first began looking at varying the application rates when the price of anhydrous began to soar a few years ago. He purchased an inexpensive valve that was wired to a power window switch. Pushing the valve one way raised the pressure and increased the rate for irrigated land. Pushing it the other way reduced the pressure for a lower rate on the dryland corners of their center pivots.

The nitrogen rates for different soil types on Fuchtman’s land are based on the University of Nebraska’s algorithm, according to certified crop adviser Mark Pavlik of Pavlik Crop Consulting. Pavlik grid-sampled Fuchtman’s land, breaking each field down into 3- to 5-acre zones. In areas of the fields where finished cattle had been grazed, for instance, sampling proved that residual soil nitrate levels were higher.

“Sandy soils have lower yield goals and, consequently, lower nitrogen requirements for corn,” says Pavlik. “Loam soils have higher yield goals and require more nitrogen,” with recommendations being made after considering residual nitrates present. “There is more variability for nitrogen recommendations on dryland corn because water is the limiting factor for yield,” Pavlik says.

Fuchtman purchased a hand-held GPS unit, and Pavlik loaded the zone areas into the GPS. Along with a Raven 440 monitor, Fuchtman was able to switch manually between two different valve settings, using one setting for irrigated land and the other for dryland, but referencing between the GPS unit and the monitor on zones where nitrogen had been carried over.

“It keeps you busy watching everything,” Fuchtman says about that system. However, by using grid soil samples in coordination with varying anhydrous rates, Fuchtman was able to achieve 200-bushel-per-acre corn with only 100 pounds of anhydrous on the land where the cattle had grazed and cycled nutrients back into the soil.

The Raven Accu-Flow system also includes a super-cooler mechanism that’s mounted on the toolbar, keeping anhydrous in its liquid form longer. This allows for a constant flow and application rate, even if ground speed is varied.

Automatic rate switch

Last season, Fuchtman took his system one step further, purchasing an Ag Leader Insight monitor that allows him to place a nitrogen prescription based on Pavlik’s soil nitrate zone maps and yield map data into the mechanism, so the rate would be changed automatically according to the GPS location of the tractor.

“As you go, it switches it for you,” Fuchtman says. “It worked like a dream. We had 100% satisfaction with this system as far as fitting into what we wanted to do.”

“They used a little less fertilizer” with this new system, says Pavlik. “But they are not wasting fertilizer on the sandy areas. If they get rain, they have a greater yield opportunity” by having their anhydrous placed in the correct amount on the right places in the field.

Fuchtman also maximizes his anhydrous utilization by paying attention to details. He applies anhydrous into standing cornstalks with a toolbar with 20-inch coulters with each application knife and closing discs behind the knives. In addition to Raven Accu-Flow, he makes sure that the hoses are all the same length and application knives are of the same brand. He employs a CDS-John Blue Impellicone anhydrous flow divider on the toolbar to make sure fertilizer is delivered evenly between the knives.

Fuchtman says that anhydrous is typically cheaper than other forms of nitrogen. Utilizing long-term soil nitrate testing and emerging variable-rate application technology makes it even more economical. “It can create a big savings on nitrogen,” he says.

Arens writes from Crofton.

03101441b.tif

NITROGEN PRESCRIPTION: Eric Fuchtman compares soil nitrate zone maps (left) to data fed into the Ag Leader Insight monitor, allowing him to make a nitrogen prescription for corn.

03101441a.tif

COMBINATION PACKAGE: Eric Fuchtman combines variable-rate technology, or VRT, tools and other smaller steps to make precision nitrogen application work.

This article published in the March, 2010 edition of NEBRASKA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.