Wheat School: Understanding the nitrogen cycle to reduce input losses and emissions

As the federal government has announced it’s desire for a 30 per cent reduction in fertilizer emissions, specifically from nitrogen, the name of the game now is, how?

For this Wheat School episode, Dr. Sheri Strydhorst, agronomy research specialist with the Alberta Wheat and Barley Commission, talks about the nitrogen cycle and takes a scientific approach to identify where the greatest opportunity for nitrogen loss in the way of emissions is, and how growers can combat it.

The nitrogen cycle starts when urea combines with water and produces ammonium carbonate through the way of urea hydrolysis. From there, it can take one of two pathways with different losses associated with both.

“If the nitrogen goes the way of the ammonia gas, then it is susceptible to volatilization. And that’s that loss of the nitrogen in the air, particularly when it’s broadcast on the soil surface,” explains Strydhorst. “If nitrogen goes into the ammonium form, this is a plant available form. The problem is this form of nitrogen is susceptible to loss through the atmosphere through denitrification.”

The depth at which the nitrogen is placed can have a big impact on potential losses as well. Strydhorst says if possible, three to four inches below the surface is ideal for mitigating volatilization losses, however, there are products that can be added if that depth isn’t feasible.

“If nitrogen is shallow banded, so less than two inches, particularly those growers who, if they’re seeding at one inch depth, that nitrogen is only being put at two inch depth, and that is still very susceptible to loss through the volatilization process. So something like a urease inhibitor like an Agrotain-type product will prevent this if deep banding is not possible,” says Strydhorst.

Growers also need to be mindful of their soil composition and their climate in order to make educated decisions on their nitrogen management. In the episode below, Strydhorst goes through these and other factors producers should consider to maximize nitrogen performance and reduce emissions.

For the full library of Wheat School episodes, click here.

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