SuperU, a nitrogen efficiency enhancer, will soon be more readily available in Western Canada. In September, Koch Industries announced that it will begin producing its SuperU at its nitrogen plant in Brandon, Man. Make that one more nitrogen efficiency enhancing product to add to the already confusing list.
Nitrogen efficiency enhancers are used to minimize nitrogen losses. The makers of these products don’t claim that they will increase yields or make up for under-applied nitrogen, but there is science behind nitrogen efficiency enhancers, and they can help lower nitrogen loss.
Nitrogen efficiency enhancers can be divided into three categories, based on how they work.
1. Urease inhibitors
This category includes Koch Industries’ Agrotain, SuperU and Agrotain Plus. Agrotain, says John Kruse, research agronomist with Koch Agronomic Service, is “a liquid product that has a unique solvent that you can actually pour on to urea.” Typically, this is done at the retail site. “You would order your urea and you request that it be protected with Agrotain. It comes in a nice green colour.”
Suface-applied urea or UAN can easily be lost to the atmosphere. The key ingredient used to battle this is NBPT (N-(n-butyl) thiophosphoic triamide).
As the category name suggests, NBPT “inhibits” the urease enzyme that causes the urea to break down into ammonium. When this conversion is slowed, there is less volatilization. It’s not a long-term solution — the products will degrade after a few days — but it does give rain or irrigation time to move the urea or UAN into the soil before the reaction takes place.
NBPT-placed products are most effective in soils that are have a high potential for volatilization — coarse soils, or soils with a high pH.
Kruse says using these NBPT products “drastically reduces the amount of nitrogen that converts into ammonia gas,” and can reduce overall nitrogen losses from 40 per cent to as little as five to eight per cent.
2. Nitrification inhibitors
This category of nitrogen efficiency enhancers includes Koch’s SuperU and Agrotain Plus, and Dow AgroChemical’s N-Serve and Instinct.
In addition to NBPT, SuperU and Agrotain Plus also use the active ingredient DCD — dicyandiamide. Like NBPT, DCD inhibits the enzyme in the soil that converts ammonium to nitrate.
Agrotain Plus is designed to be added to a liquid nitrogen fertilizer such as UAN. Kruse says, “If a farmer uses a liquid fertilizer, then he can protect that UAN from both volatilization and rapid nitrification by adding the Agrotain Plus to his UAN. It’s a light blue powder and it goes into suspension in the UAN.”
SuperU uses both NBPT and DCD to protect urea from volatilization and nitrification. When farmers choose SuperU, Kruse says, urea comes with “both inhibitors already infused into the granule.”
Dow AgroChemical’s nitrogen efficiency enhancers Instinct and N-serve use a different active ingredient — nitrapyrin. Nitrapyrin deactivates the nitrosomonas bacteria that help to convert nitrogen, slowing down the conversion process. Nitrapyrin was discovered by Dow Chemical scientists in the late 1950s; N-serve was registered in the U.S. in 1976.
Instinct and N-serve are not available in Canada now, but Dow AgroSciences is looking at market opportunities. N-serve is designed for use with anhydrous ammonia; Instinct is for use with other types of nitrogen.
3. Controlled release products
The most common product in this category is ESN.
ESN is a polymer coating applied to urea. The coating breaks down slowly, and allows the urea to diffuse out over time. Ideally, the nitrogen release can be matched to growing plants’ needs. Controlled nitrogen release is also helpful where there is high nitrogen loss from leaching or volatilization.
At a demonstration day in July, Saskatchewan Agriculture’s soil and nutrient management specialist Patrick Moolecki told farmers that ESN can also be helpful when it comes to avoiding ammonia toxicity.
“If you are using ESN, you can actually increase your rates because of that extra protection,” he said. “When you are sidebanding you can actually put on all your fertilizer, as long as you have enough moisture at seeding.”
Agrium advertises that farmers using 100 per cent ESN fertilizer can apply up to three times the normal safe rate of nitrogen in the seed row.
Because ESN can be beneficial to the environment, the U.S. government provides some financial incentive programming to encourage farmers to use them.
Roy Munton, Agrium Advanced Technologies’ Saskatchewan sales rep, says, “Another benefit of ESN that a lot of people don’t talk about is that with its coating, it doesn’t take on moisture so it runs freely and doesn’t cake or lump up in storage. It is really nice to handle compared to other granular fertilizers.”
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Nitrogen replacement economics
It might seem that farmers planning to use nitrogen efficiency enhancers could cut back on nitrogen purchases, spending about the same amount of money in total.
John Kruse says using these products is not a direct route to using less fertilizer. “That’s the challenge. Every farmer’s field is different. Every year is different… We don’t necessarily go out and tout that you can cut back on your nitrogen. What we tend to feature is the opportunity for increased yields at level nitrogen rates.”
Another apparent option might be to skip the nitrogen stabilizers and spend the money on extra nitrogen. But a question and answer presentation by Dow AgroSciences makes this point: “If you are adding more nitrogen than you need to produce a crop, then you know you are losing nitrogen. Nitrogen loss cannot be fixed by adding more nitrogen.”
Dow makes a colourful comparison: “Adding more water to a bucket with a hole will result in additional water loss.”
John Heard is a soil fertility specialist with Manitoba Agriculture, Food and Rural Initiatives. Heard has studied these products and says there is a scientific basis to most of the nitrogen enhancers on the market. Sales reps should be able to explain their products’ processes as part of the nitrogen cycle, he says. “The onus of proof is on the marketer of the product. They better have a good scientific explanation of how it works.” If you don’t fully understand the science behind the product claims, Heard recommends that you ask a certified crop adviser to help you make the decision.
While the products discussed here and others on the market do have a basis in solid science, Heard says, “none of them are any improvement over right rate, right time and right place.” Heard is referring to the four Rs of fertilizer use endorsed by the International Plant Nutrition Institute (right fertilizer source, right rate, right time and right place).
Nitrogen efficiency enhancers aren’t better than best management practices, but if something should go wrong, such as excess water, these products can help to minimize loss. “If you can put it into high risk situations,” Heard says, “that’s where you expect the payback.
“They do work,” he says, “but they aren’t needed every year. Unless you’re suffering a lot of rain or wet conditions you should end up with about the same yield.” Heard suggests that farmers think of these products the same way they think of insurance contracts: if you applied them and they weren’t necessary, that’s probably a good thing.
And, keep in mind that while these products aren’t an improvement over best practices, Heard says, “but they all cost more money.”
As for the expansion of the Koch Industries operation, Heard says that, in the past, Prairie farmers had limited access to SuperU. “Now we’ll have a local source.” With farmers using more of these products and losing less nitrogen, Heard says, “the environment could benefit.”
Find John Heard’s information bulletin online at www.gov.mb.ca. Search the site for “nitrogen efficiency additives.”