Last week I introduced the topic of smart nitrogen and talked about why it's time is coming, if not already here. This technology may help cope with tighter environmental regs, shorter planting windows and wild weather.
Polymer-coated uruea is fertilizer that delays the availability of nutrients to plants following application. Right now Agrium's ESN (Environmentally Smart Nitrogen) is the only controlled-release nitrogen source widely available for broad-acre agriculture.
How does a polymer-coated urea work? The release rate increases with temperature and decreases with coating thickness. Once it is applied to soil, ESN absorbs moisture, and as water moves through coating, urea oozes out into the soil, over time. "For each 18 degrees F rise in temperature the rate of nutrient release about doubles,” says Eric Ellison, Agrium agronomist. In this video, Attica, Ind., farmer Kenny Brown explains why he uses ESN.
ESN releases nutrients over a 60 to 80 day time period depending on soil temperature. Once it is released it behaves the same as any other urea product.
The product costs about 18 to 20 cents more per pound of N compared to conventional urea. Although ESN costs more, you may be able to eliminate an early season sidedress application, because slow release nutrients keep offering nutrients to the plant as the growing season goes along.
"We can eliminate split applications that involve tractor passes and wheel traffic and really simplify fertilizer applications," says Ellison.
Agrium officials tell me there is growing interest in ESN, citing significant growth in sales since 2009. They also say it's not just about eliminating N loss or fewer field trips; It's also about boosting yield.
"In University studies in soil conditions conducive to N loss, we saw 15 to 20 bu. per bu. corn yield increases," says Alan Blaylock, agronomy manager at Agrium. Those conditions included volatilization, nitrate leaching and denitrification from ponding.
"We need to apply them when you are at the part of the curve where you are still getting a yield response, and not reaching over the top where the yields begin to dip no matter how much you apply," says Ellison.
Blaylock admits that when weather cooperates and N loss is minimal, the yield impact may be negligible. "On the other hand, we've had a run of five to six wet years, and that's where ESN shines," he adds.
Smart fertilizer is perfect for fields adjacent to waterways or land that gets intensive fertilizer or manure applications. It is also good for sandy soils prone to leaching, or soils closer to shallow aquifers.
Because polymer coated technology protects nutrient loss it is considered an environmentally friendly farming practice and is therefore eligible to receive payments through the government's Environmental Quality Incentives Program (EQIP). Those payments, which run anywhere from $5 to $15 per acre, can help offset the higher cost, so it's something you'll want to investigate if you use the product.
"Farmer surveys show yield and convenience will drive sales of ESN," says Blaylock. "Farmers are concerned about the environment, but it doesn't drive their decisions.
"Slow and controlled release fertilizers are tools to minimize environmental impact of nutrients, but more importantly for farmers, they can improve yield, quality and net returns," he concludes. "Every pound of N that goes into the water is a pound of N you paid for and you lost."
Video linked with permission from Agrium Advanced Technologies