Controlled release urea | Benefits fail to outweigh the costs, except under specific conditions
Applying controlled release fertilizers on wheat, barley and canola isn’t worth the extra cost in Western Canada, Agriculture Canada researchers have concluded.
In a study published this spring in the Canadian Journal of Plant Science, Mohammed Khakbazan, an agricultural economist with Agriculture Canada in Brandon, determined that the rate of nitrogen application had the most impact on crop yield and net revenue.
In contrast, choosing a controlled release urea (CRU) fertilizer had little impact on the net revenue in barley, canola and wheat in plot trials conducted across the Prairies.
“In general, the application of NCU (non-coated urea) produced similar or higher returns than the use of CRU, split fertilizer applications or a blend of NCU and CRU,” Khakbazan wrote in the paper.
The conclusions are fairly straightforward, but Cindy Grant, a soil fertility specialist with Agriculture Canada in Brandon, said the message to farmers is more nuanced.
Grant, who co-wrote the research paper with Khakbazan, said banding nitrogen with the seed is the “gold standard” for fertilizer application in Western Canada.
It doesn’t mean canola, barley and wheat growers should avoid controlled release fertilizers, but they should understand why, when and where to use them.
Grant offered four scenarios where a producer might want to choose a coated, controlled-release fertilizer such as Environmentally Smart Nitrogen, an Agrium product, or a nitrogen stabilizer such as Agrotain, made by Koch:
- When conditions are wetter than usual.
- If a grower is broadcasting fertilizer because of time or labour constraints.
- If a producer is seeding winter wheat and wants to apply the fertilizer in the fall.
- If a grower is using high fertilizer rates that might jeopardize seed safety.
Grant said controlled release products are better suited for warmer and wetter regions, such as Ontario and Quebec, where there is a greater likelihood of nitrogen loss.
“There’s a short time (on the Prairies) between when you’re seeding the crop and when the crop is starting to take up nitrogen rapidly,” she said.
“(Unless) you get extremely warm and wet conditions during that time period, then your losses … are going to be pretty low…. If you’re not having a lot of losses, there’s not an economic (necessity) to try and fix those losses.”
Ray Dowbenko, an agronomy specialist with Agrium, didn’t argue with the data in the Agriculture Canada study. He agreed there are places and times where controlled release urea is more useful
“Based on what (Grant) says, I agree 100 percent. There is no point in using these products if we don’t think there’s going to be value for the grower.”
Dowbenko said growers shouldn’t use controlled release urea on a whim, just because they want to give it a try.
“That’s a mistake with these products. You have to be clear in your mind why you are using them and what you hope to accomplish.”
For instance, highly variable climatic conditions on the Prairies can create times when the products are beneficial.
“We can have extremely wet soils coming out of winter,” he said.
“We can have (significant) rainfall events during the growing season.”
Dowbenko said enhanced efficiency fertilizers are better suited for wetter regions, sandier soil and crops such as potatoes, corn, fruits and vegetables.
“Broad acre crops like wheat and canola, it (the usefulness) is still there, but it’s not as sweet a spot as some of the high value crops.”
Based on a Statistics Canada survey of environmental farm practices, Grant said 70 to 80 percent of growers band fertilizer with the seed in Western Canada.
There’s no doubt that spreading fertilizer is less efficient than banding, Grant added, but other factors, such as a time crunch during seeding, might force a grower to spread fertilizer.
“That extra handling and extra time to band things in can be problematic,” she said.
“Time and labour are also very scarce commodities. You may be willing to (accept) a 10 percent loss in nitrogen use efficiency, to make sure you get your crop in on time.”
Grant said growers who choose to use controlled release fertilizers shouldn’t treat them as a substitute for proper agronomic practices.
“They’re not excuses (for) poor fertilizer management,” he said.
“Unfortunately, some people look at these tools and say, ‘well, I can do it this way, (even though) it’s not that efficient.’ ”
Dowbenko and Grant said it’s reasonable for growers to view controlled release fertilizer as insurance against adverse or unknown conditions.
Producers typically buy fertilizer in advance and it’s difficult to predict if nitrogen losses will be a risk several months before application.
Dowbenko said growers should consider using a percentage of enhanced efficiency fertilizers in their operation to hedge against potential nitrogen losses.
“Often for wheat growers in Western Canada, we recommend 30 or 40 percent of a controlled release product, not 100 percent.”
The million dollar question for producers who want insurance against nitrogen losses is how much to pay for that insurance.
“If you’ve got higher risk, you’re willing to pay more,” Grant said.
“If you have a low risk, you probably aren’t willing to pay for insurance.”
- At 7 C, five percent of the urea is volatized as ammonia after eight days.
- At 24 C, 12 percent of the urea is volatized after eight days.
- At a soil pH of 6.5, 11 percent of the urea is volatized after six days.
- At a pH of 7, 23 percent of the urea is volatized after six days.
- In Western Canada, ESN sells at a $90 to $130 premium to conventional urea.
- Agrium opened its ESN plant in Carseland, Alta., in 2006 and expanded its ESN plant in Missouri last year.
- The company can now produce 481,000 tonnes of ESN a year.
- Sales were 284,000 tonnes last year, up from 213,000 in 2010 and 156,000 in 2009.
- Agrium’s Advanced Technologies division, which produces slow and controlled release fertilizers, had revenues of $578 million last year and $510 million in 2011.