Enhanced efficiency nitrogen fertilizers useful tool for sustainable nutrient management

Agriculture contributes to roughly 10 percent of Canada’s total greenhouse gas emissions, most of which are in the form of nitrous oxide (N2O). Levels of this powerful gas are rising, in part due to the growing use of synthetic nitrogen fertilizers, but researchers at the University of Saskatchewan believe the adoption of enhanced efficiency nitrogen fertilizer (EENF) can help manage the situation. 

Saskatchewan producers rely heavily on synthetic nitrogen fertilizers for the success of their operations. The application of these products supports plant growth by increasing availability of the essential nutrient. Unfortunately, microbes in the soil like to break down nitrogen in the soil which leads to the generation of N2O gas. Not only does this represent a growing environmental risk, but it also represents a significant economic loss for the producer. 

The development of EENF products comes as a solution to both of these challenges. They are designed to control the release of applied nitrogen into the soil, giving the crops a better chance to compete against soil microbes for this essential nutrient and mitigating the production of greenhouse gases.

“It’s all about synchronization,” says Dr. Richard Farrell, Associate Professor with the University of Saskatchewan’s College of Agriculture and Bioresources and Chair of Soil Biological Processes with the Saskatchewan Ministry of Agriculture’s Strategic Research Program. “The EENFs help make sure that nitrogen is still in the soil when the crop starts putting down roots and is able to take it up. Once the crop is established, it will outcompete the microbes for that nitrogen.”

In other parts of the world, adopting EENF products into commercial agronomic practices has shown promise for reducing industry N2O emissions, but what about in the Canadian Prairies?

Dr. Farrell and a team of researchers from the University of Saskatchewan decided to take a closer look. Thanks to funding support from the Saskatchewan Wheat Development Commission and the Saskatchewan Ministry of Agriculture through the Agricultural Development Fund, their research was able to evaluate the effects of EENF products on N2O emissions in Saskatchewan cropping systems.

As Dr. Farrell explains, “We wanted to see how EENFs would work in Saskatchewan’s irrigated and non-irrigated systems when applied either in the fall, or in the spring.”

The three-year project took place in the black soil zone of the province, near the town of Broderick. After applying different EENF products to the test plot soil, the research team got to work measuring levels of N2O gas escaping the soil. 

“We decided to look at a variety of urea-based EENFs including polymer coated products, nitrification inhibitor products, urease inhibitor products, and products with both a urease and nitrification inhibitor,” says Dr. Farrell. 

Based on their findings, each of these products reduced N2O emissions by upwards of 30 and 50 percent, regardless of cropping system or timing of application.  

“The products that had the urease inhibitor were effective in the spring, but less effective in the fall,” says Dr. Farrell. “The polymer coated products reduce N2O emissions after spring application, but not as well as the other products; the products containing a nitrification inhibitor were effective at reducing N2O after both spring and fall applications.”

These results point to a possible win-win scenario. Reducing greenhouse gas emissions can help mitigate climate change, while the controlled release of nitrogen could safeguard a producer’s fertilizer investment.

“It's exciting to be involved in something like this,” says Dr. Farrell. “The goal for Canada is to reduce greenhouse gas emissions and using products like these EENFs is going to be a key element to doing that.” 

According to Dr. Farrell, “EENFs certainly have their place as a sustainable nutrient management tool, but we need more information to be able to give reliable recommendations on how to optimize the agronomic benefits of these products in Prairie cropping systems.”

The information gathered through this trial is a great start and Dr. Farrell’s team are continuing to build on this knowledge to help ensure the long-term sustainability of Saskatchewan cropping industry.  

“We’re certainly making progress, “says Dr. Farrell, “and we’re building up enough data to start making some recommendations in the near future.”