Turn on the TAPPS for better nitrogen efficiency

LANGHAM, Sask. — Farmers at the recent Ag in Motion show who want to optimize nitrogen uptake were drawn to the rubber- track trailer bearing a pair of 1,200 gallon liquid tanks flanked by a pair of 2,000 gallon anhydrous ammonia tanks.

The big rig was the brainchild of Crop Production Services in Sexsmith, Alta., according to fabricator David Paulson, owner of Wadena Steel. AIM was the first public showing of the TF4024 project.

“Once we get the Exactrix pumps installed at the back, we’ll be producing what they call TAPPS fertilizer,” said Paulson of Wadena, Sask.

“TAPPS is tri-ammonium poly-phosphate sulfate. The sulfate and phosphate are in the two liquid tanks, and of course nitrogen in the anhydrous tanks. The idea is that it stabilizes your nitrogen. This is fairly new in Canada. There’s a guy in Alberta who’s been doing it for a few years, but this is my first opportunity to build a machine like this.

“The tracks are from Soucy, with duals in front. They’re calculated to carry the weight of 30,000 pounds empty and 80,000 lb. full, about the same weight as a semi. There’s no brakes on the machine. To build another unit, I figure it would sell for about $260,000 with the Exactrix equipment.”

Blaine Richter, a CPS agronomist in Sexsmith, Alta., said nitrogen likes to run away, particularly in the nitrate format.

“The goal of this TAPPS custom application project is to bring stabilized nitrogen to producers in the Peace River in a more affordable format,” he said.

“It’s a well-known fact that if you mix bio-salt liquid sulfur with ammonia, you get a stabilized band that lasts as long as eight weeks. We’re such a heavy canola region, so we’re already applying 15 pounds sulfur per acre per year anyway. So we’re killing two birds with one stone.

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“Then we also mix in liquid phosphorous. That’s 10-34-0 ammonium poly phosphate (APP) to bring all our fertility into a single pass. All this goes down in the fall, so the grower doesn’t need to think about fertilizer applications in the spring.”

Exactrix supplied the pump, meter and application tools. The mix will enter the soil through P51 Mustang CUE openers on 24-inch centres. CPS chose P51 high speed discs because a secondary goal of the project is to make the machine snow-proof. Richter said CPS wants the ability to band fertilizer in all weather conditions. Even in snow, the fertilizer band goes all the way down to the targeted seven-inch depth.

“We’ll be able to work right up until December without experiencing the classic frozen football or mud-ball buildup,” he said.

“We typically get snow before the ground freezes. This really opens up our window for fall application. With the Mustang discs, this machine can work in two feet of snow.

“It’ll roll through six inches of snow with pure mud underneath. The discs never ball up. We can apply fertilizer in places where you can’t drive a pickup in the field. That’s why we have tracks on the cart and we’ll be using a quad-type four-track tractor to pull it.”

NH3 always likes to be friendly with H2O, but Richter said that’s not a big factor in the TAPPS strategy. It takes very little water to convert ammonia to ammonium, he added.

Richter said uniformity is a major part of the scheme. Conventional pressure drop injection systems drip ammonia in the ground. They dribble the fertilizer into the trench. Liquid systems have the same drawback he added.

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“The TAPPS system squirts fertilizer in behind the disc through a .038 inch orifice at 200 p.s.i.,” he said.

“The orifices are underground just behind the disc, and they squirt at an angle at the thinnest part of the disc. It actually mixes in a very small ribbon. The pump itself operates anywhere from 150 p.s.i. to 300 p.s.i. Once you get above 100 p.s.i., the function of the pressure doesn’t change much. Above that, you have all the flow you really need.”

Guy Swanson, the agronomist at Exactrix who led development of TAPPS, said in a telephone interview that the liquid poly phosphate up at the manifold starts at about 300 p.s.i., but it’s much lower when it goes through the injector so it doesn’t splatter.

“There’s a partial vacuum created behind the disc. We drive in the liquid poly phosphate first, before the NH3. The liquid is sucked in by the vacuum,” he said.

“Next, the ammonia comes shooting into that liquid at high pressure, usually up to 300 p.s.i. It’s moving at 80 or 90 m.p.h. and it’s hungry for hydrogen. It finds the poly phosphate and makes the reaction. And that’s the point at which it crystallizes and becomes stable.

“All this is happening at a recommended ground speed of about eight m.p.h. It works at speeds down to four m.p.h., but not as well. And it works up to 12 m.p.h. in the field. The disc needs forward momentum to create the vacuum.”

The Sexsmith project will tie onto a 61 foot Case 940 Nutri-Placer. Richter said the Mustang discs have such low-disturbance that growers also use the rig to apply anhydrous ammonia in winter wheat in the spring, in which case the machine is run at an angle across the rows.

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“It’s a very flexible system that accounts for rate, ground speed and orifice size,” he said. “It’s controlled by our echelon variable rate system, which lets us vary rates of N, P and S independent of each other.”