Enhanced efficiency fertilizer (EEF) is a blanket term referring to products that optimize nutrient uptake and prevent nutrient loss by controlling the speed of release or altering soil-fertilizer reactions.
EEFs intended for agricultural production are commonly nitrogen products, although the technology has been applied to other nutrients such as phosphorous. While agricultural use of EEFs is not widespread in Canada — until recently they were more commonly used in the turfgrass and horticultural sectors — interest in the potential value of EEFs for maximizing profit and benefiting the environment is increasing.
“Depending on the product, what enhanced efficiency fertilizers generally do is release the nutrient in a controlled pattern that matches with crop uptake,” says John Gibson, western sales manager for Agrium Advanced Technologies.
Agrium produces Environ-mentally Smart Nitrogen (ESN), a temperature controlled-release polymer-coated nitrogen fertilizer. ESN protects against the three loss mechanisms for nitrogen — leaching of nutrients below the root zone, denitrification, or loss of nitrogen to the atmosphere in the form of nitrous oxide, and volatilization, loss of nitrogen in the form of ammonia gas. According to Gibson, ESN is the only product in the market that protects nitrogen against all three loss mechanisms, with the added benefit of maximized yield and quality.
“When we have these loss events, whatever nitrogen is in the soil in the nitrate form is susceptible to that leaching down through the soil, or it can volatilize as it converts to gas,” explains Alan Blaylock, manager of agronomy for Agrium. “ESN allows only a small amount of that nitrogen to be released at a time.”
ESN uses a polymer coating to deliver the fertilizer slowly, with the rate controlled by temperature and moisture.
“Depending on the enhanced efficiency fertilizer we’re talking about and its effectiveness in preventing loss, we may be able to achieve the same result with one application that we might achieve with multiple applications,” says Blaylock. “In many cases it’s recommended that you split nitrogen applications into several applications, but that costs the farmer more fuel, more labour. With ESN we’re substituting fertilizer for mechanical applications.”
Agrotain is another type of EEF, a nitrogen stabilizer which can be blended with urea and liquid nitrogen UAN fertilizer, and which works by blocking the enzyme urease, slowing nitrogen loss.
Stewart Brandt, field research manager for Northeast Agriculture Research Foundation, has worked on field trials with Agrotain and ESN, testing how much product can be applied with the seed.
“With Agrotain, early indications were that you could apply more, and the research that was done at that time substantiated that. With the polymer coating the amount you could apply was three times higher than what you could apply with untreated urea in the seed row with the seed,” he says.
Brandt believes EEF products have merit particularly in situations where farmers only have equipment that places fertilizer in the seed row, their only alternative being to broadcast the fertilizer on the soil’s surface. According to Brandt, EEFs are a good fit for growers using zero-tillage farming, unless they’re using banded fertilizer in advance of seeding.
“Most growers are adapting their management systems to the conventional forms of fertilizer nutrients, so they don’t need to apply nitrogen on the soil surface—most of it is banded in some form but is not applied with the seed,” he says. “For seed growers, for example, if you need to apply nitrogen in that situation something like Agrotain might be beneficial because the option doesn’t exist to apply that with the soil—it has to be applied on the soil surface.”
EEFs tend to be pricey, and farmers might question whether they’re worth the premium. But according to Gibson, evidence has shown great results. “Depending on the inclusion rate, ESN costs anywhere from nine to 15 dollars more than the conventional rate, but typically we get a three to six bushel increase on spring cereals, an eight to 10 percent increase on canola and the potato data is so good you’d call me a liar if I told you,” he says.
A clear benefit of EEFs is the protection they offer against the risk of environmental damage through leaching, denitrification and volatilization. But that’s not the only benefit. According to Blaylock, EEFs save producers from losses long-term by increasing use efficiency.
Whether or not products like ESN show dramatic yield increases, less nitrogen lost through leaching is less nitrogen — bought and paid for — lost to a farmer’s pocketbook. And farmers make fewer trips to the field, saving on gas and labour.
“Anything we can do to prevent [nutrient] losses should have a positive impact for the farmer,” says Blaylock. “Stopping those losses doesn’t always influence yield, but we get more of the nitrogen we apply into the crop, and we get a better crop. Or we can grow that crop with less fertilizer. If we’re reducing the loss we can grow that crop more efficiently.”
However, Blaylock warns against using EEFs as a blanket solution. “There are many different products and different modes of action and they don’t all work the same and they are not interchangeable,” he says. “EEF is a broad umbrella term that includes a lot of products. In the end you need to understand the mode of action of the product and match it with the problem you’re trying to solve.”
EEFs have a role to play within the 4Rs of nutrient stewardship — using the right product, at the right rate, at the right time and in the right place — and may be a good bet for farmers looking to improve efficiency and minimize potential impacts on the environment. †