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Practical options for variable rate NH3 systems

Variable rate farming has been around for years but with the new technology, it’s becoming more popular and easier, says Tim Ottenbreit, Raven Industries Canada sales manager, from his Stockholm, Saskatchewan, office.

November 21, 2011  By John Dietz

Variable rate farming has been around for years but with the new technology, it’s becoming more popular and easier, says Tim Ottenbreit, Raven Industries Canada sales manager, from his Stockholm, Saskatchewan, office.

Technology for variable rate anhydrous ammonia is now more common. Photo by John Dietz.


“Guys are receiving a payback on it. It’s definitely getting adopted by the farming community,” Ottenbreit says.


Raven, Capstan, Tru-Kare and Maxquip are four companies building anhydrous ammonia (NH3) systems that operate with sectional controls and handle application zone prescriptions. The systems shave input costs, offering a fairly short return time on the investment.

Tru-Kare and Maxquip claim they have zero freezing issues with anhydrous injection. They use pumps to increase pressure in the lines and keep anhydrous liquid until it leaves the openers.

Most manufacturers claim that, like autosteering, the investment cost for variable rate NH3 is soon offset by the benefits. This is often the case; for instance, a registered seed grower with about 5000 acres calculated that he saved enough in just one season to recover the roughly $25,000 investment.
Capstan Ag Systems captures award
Best New Product at Manitoba Ag Days 2011 in Brandon went to the Capstan Ag Systems N-Ject technology. It was fresh in Canada in 2010 but had been available in the U.S. market since 2007. Capstan is located at Topeka, Kansas.

Western Canada field marketing representative Garnet Welykholowa said Capstan is well known for SharpShooter and AIM Command. These systems are installed on high-clearance sprayers to control boom pressure and droplet size.

 “Sectional control is in very high demand now, and farmers want to use anhydrous when they seed,” Welykholowa said. “The savings alone for sectional shutoff is from seven to 14 per cent. In addition, a lot of producers want to go to a variable rate fertilizer application program. That’s why they are looking at systems like our N-Ject.”

N-Ject is available as an after-market installation on any OEM toolbar, air drill/seeder or planter. It works with most rate-control systems on the market and uses the existing tank pressure.

According to Capstan, it is a “simple, clever automatic ‘orifice’ changer,” that ends the need to change orifices for different rates or speeds. Each NH3 outlet on the toolbar has its own Pulse Width Modulation (PWM) solenoid valve to control the outlet flow.

Liquid anhydrous passes from the tank through two cooling blocks and into the solenoids below. The solenoids meter only liquid NH3, using pulses to give a controlled, accurate flow rate.

According to Capstan, the system has a 25:1 variable rate range and immediate overlap control for each implement section. Product placement is both accurate and even.

DyTerra Corporation, distributor for the N-Ject system, has offices in Winnipeg, Saskatoon and Calgary.

DyTerra has installed the N-Ject system on machines from 60 to 80 feet wide and with three, six or nine sections. Each system is custom fitted. A 65-foot machine with six sections will be priced around $27,000 to $30,000.
Tru-Kare uses streaming liquid injection
A Lacombe, Alberta, company that specializes in NH3 equipment has paired up with an American company, Exactrix, to adapt industrial-type NH3 equipment for the farm market. Blackbird SR71, according to Tru-Kare, is designed for variable rate application. Introduced in 2009, the Blackbird SR71 adapts to most controllers. It promises to eliminate freezing boots and lines and to improve accuracy at faster speeds in cold weather.

According to Richard Enns, Tru-Kare president, his Blackbird SR-71 is the only one of three high-pressure anhydrous systems that really delivers streaming liquid injection.

Enns says, “When your injection nozzle is 12 inches long, you’re back to a gas by the time your anhydrous hits the soil. There are significant differences in application systems, even though they sound similar.”

The Blackbird has a machined orifice for each injector. The cold liquid stays at 20 to 50 psi above tank pressure and within a coefficient of variance of only one percent, shank-to-shank. “You can only do that with a machined orifice,” says Enns.

Tru-Kare offers its system only at the one shop at Lacombe. Customized kits are prepared for each customer. It’s best suited to systems with shank openers but adapters for single disc openers are available. With output up to 140 psi, Blackbird can accommodate field speeds to 7 or 8 mph.
For systems from 50 to 71 feet wide, the cost is roughly $30,000 to $45,000, Enns says. Farm size for the break-even on investment, due to reduced input costs, is about 5,000 acres.

According to Enns, the Blackbird is highly responsive.

“We have ability with a 70-foot machine to go down as low as 20 pounds per acre and back up to 140 pounds per acre in three seconds,” he said. “That’s critical when you do variable rate. If you’ve got a slow response machine, you could be out of the zone by the time your rate changed.” 

Response time will vary among rate controllers, he says. Fastest among the controllers he’s tested is the Dickey-John. “It doesn’t have the capability of controllers like John Deere or Topcon, but it’s relatively cheap and is the fastest.”

Maxquip develops variable rate system
Founded in 2002 in Calgary, the Maxquip company styles itself as a global value-added supplier of innovative solutions. The company discovered issues with application technology for anhydrous, and in 2007 came up with a product they believe is better.

Maxflow Variable Rate Control (VRC) is described as, “A high-pressure, high-rate ammonia fertilizer pumping system that provides up to 30 percent higher application speed than standard systems (and) eliminates opener freezing.”

It can accurately meter NH3 from rates as low as 4 gpm (1,000 pounds of nitrogen per hour) to as high as 40 gpm (10,000 pounds of nitrogen per hour), according to Brent Grant, product spokesman.

Maxflow VRC uses a specially designed positive displacement Blackmer pump. Application rates adjust with the pump speed, which is hydraulically driven. Fast-acting electric shut-off valves for sectional control are typically installed on each manifold.

“Every kit is tailored to the producer’s requirements,” Grant said. “We have farmers with 1,500 acres and with 25,000 acres.”

Maxflow VRC has been installed on applicators from 30 to 84 feet with anywhere from two to eight manifold control sections.   

Systems are sized so that manifold pressures are maintained at or above tank pressures to improve distribution accuracy. Distribution lines from the manifolds to the openers are cut to equal lengths. They are very easy to interface with most openers. For some openers, a stainless steel tube is used to aid in accurate placement of the anhydrous ammonia.

“Rate changes from a lower to a higher rate happen very quickly, while rate changes from a higher to a lower rate will take a little bit longer with most applicators,” he said.

Feedback from Maxquip dealers across Western Canada for mapping programs linked to the VRC through a controller indicates that the Maxflow VRC is very responsive and very accurate.

“One fairly large seed producer paid for his system the first year, based on the overlap he did not have with anhydrous. He has a very sharp pencil, and GPS sectional control.”

Raven system updated
Response time can be an issue for a prescription map or section shutdown, but it also can be overcome by the field computer that’s programmed for the function, says Raven’s Tim Ottenbreit.

Raven’s latest ViperPro can control rates separately for up to four granular products and anhydrous.
“When you’re coming into the next zone, the controller is looking ahead. It’s adjusting that rate before you get to that zone, so that it’s on target as you enter,” he says. Raven field computers also connect to the Maxquip and Capstan systems for simple variable rate application, section control and rate control.

In addition to delivering variable rate anhydrous with these systems, Raven has its own products for anhydrous application, says Ottenbreit. Raven SuperCooler delivers up to 30 gallons per minute, and has been in use for many years. It was updated in 2011 with the Raven HP System.

“With this system, we connect two SuperCoolers and use the hydraulic pump to pump anhydrous out to the toolbar. The market for the HP System is strong in the Corn Belt where guys wants to travel at high speeds and high rates in cooler fall weather,” says Ottenbreit.

Another product, Raven OmniSeed, looks like an important innovation for variable rate and sectional shut-off controls with anhydrous. It was introduced in June 2011 at the Farm Progress Show.

Essentially, where ViperPro is the field computer, OmniSeed can reduce controller clutter in the cab while controlling all air cart functions. The OmniSeed system will fit most air tanks. Very fast rate changes are possible with the hydraulic motor that controls the tank meters. OmniSeed also controls most tractor functions, from autosteer to Agtron Blockage.


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