ROULEAU, Sask. – Nitrogen fertilizer management with direct seeding can be difficult. While many drills are able to put down all the fertilizer in a separate band from the seed, there are still times when high levels of nitrogen might damage emerging seedlings.
Surface-applied nitrogen is less efficient than banding, and if using urea, much of it can be lost to the atmosphere unless rain moves the nitrogen into the soil.
A fertilizer additive developed in the 1980s and registered in Canada four years ago is one option farmers have to manage their nitrogen and reduce the potential for seedling burn and nitrogen loss.
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The active ingredient in Agrotain inhibits the ability of the enzyme urease to convert urea into the ammonia form of nitrogen. Urease is found everywhere in the soil, especially around decomposing plants. Agrotain stops urease from converting urea to ammonia for about seven days. As the Agrotain breaks down, it allows the conversion to proceed slowly, so after about two weeks, the urease is again able to convert the urea.
With this one to two week delay, seedlings are able to germinate and increase their tolerance to ammonia. Any rain in this period will move the urea into the soil or reduce its concentration in the seed row, to help limit any potential for damage.
“We see a good fit in situations where surface-applied urea is an issue – with forages, grass, winter wheat, where zero-till guys want to top-dress, or where they’re concerned how much N can go down the spout,” said David Hansen, Canadian marketing manager for Agrotain.
“As long as the N remains in the urea form, the risk of damage is minimal. By delaying the release of ammonia, there’s more time for germinating seedlings to establish.”
Hansen said with narrow openers used by many direct seeders, the limit for seed row applications of urea is about 10 pounds per acre in crops like canola. Even with side banding equipment, many farmers are interested in ensuring the urea applied at seeding time is safe for the seedlings.
He said independent research across North America, at universities and government research stations shows Agrotain reduces urea-based nitrogen toxicity to canola seedlings and improves canola plant stands.
In the 20 years the urease inhibitor has been available in the United States, it has been tested on a range of crops, including top-dressed corn, forages and winter wheat.
Clayton Kuchinka, a fertilizer dealer in Macoun, Sask., said some of his customers have used Agrotain for the past four years as a seed safety tool with canola and flax.
“They’re seed placing it, with a single-shoot air seeder. We Agrotain about 30 percent of what’s going in the ground, to delay the release. One guy was putting on about 110 lb. of 46-0-0 with canola, all going down with the seed, and 30 percent of that was Agrotained,” Kuchinka said.
In higher moisture areas, like Lancaster, Ont., Bruce Monroe of Monroe Agromart said farmers use Agrotain to side-dress urea between corn rows, instead of using anhydrous or 28-0-0.
“We also use it in cereals and hay fields. It opens the door to using urea, which is often a cheaper form of nitrogen.”
Hansen said Agrotain can be used on granular urea (46-0-0) or liquid urea ammonium nitrate (28-0-0).
Retailers will apply the Agrotain to granular urea before it’s delivered to the farm. With liquid UAN, it can be mixed at the retail outlet, or directly on the farm, Hansen said.
“With dry fertilizer, you’ll add five to 8.5 cents a lb. to your nitrogen costs. With liquid, you add four to seven cents a lb.”
The additive has three recommended rates – a five to seven days, eight to 10 days, and 11-14 days. The liquid product goes on at three to five litres per tonne of granular product, or half that with 28 percent solution. The higher rates simply provide a longer period of protection.
Agrotain is available at most fertilizer dealers and line company outlets that sell fertilizer.
