Fertilizer Emissions Research Could Improve Farm Efficiency

Olds College of Agriculture & Technology is a key part of a national research program that’s studying ways to reduce farm emissions of a potent greenhouse gas, potentially boosting profits for producers.

“Emissions of nitrous oxide, or N2O, from agricultural soils are primarily from nitrogen fertilizer,” said Maurizio Comandone, a PhD student at the University of Guelph who is undertaking research at Olds College as part of the CanN2ONet program.

“This gas significantly contributes to the greenhouse effect, with each molecule having the same warming effect as 273 molecules of CO2. Imagine if farmers knew the perfect spot and exact amount for their fertilizer. They could potentially lower soil emissions, but also get better yields for their crops while no longer throwing money away on wasted fertilizer.”

Led by the University of Guelph in Ontario, CanN2ONet was launched last year using $7.9 million in federal funding. The four-year research program aims to help Canada reduce fertilizer-related N2O emissions to 30 per cent below 2020 levels by 2030.

The program includes Olds College and Lethbridge Polytechnic in Alberta, along with the University of British Columbia, University of Saskatchewan, University of Manitoba,  McGill University in Quebec and Dalhousie University in Nova Scotia, said Comandone.

“We wanted to create an entire network across Canada that will include different regions, environments and crops. The goal is to give new tools to farmers, society and stakeholders, especially the government, so they can measure, evaluate and tackle this problem.”

The 2023 Global Nitrous Oxide Budget report by the Global Carbon Project said agriculture is the world’s largest source of human-caused N2O emissions, accounting for about 74 per cent of the total in the 2010s.

These emissions mostly happen when nitrogen-rich synthetic fertilizers and animal manure accelerates natural microbial processes in the soil. The U.S. Environmental Protection Agency estimated in 2023 that N2O emissions from agriculture can persist in the atmosphere for about 121 years.

Research at Olds College seeks to determine if precision agriculture is an effective way to reduce these emissions. It’s a farm management strategy that uses sensors, digital tools and other information technology to ensure crops and soil receive exactly what they need for optimal health and productivity, said Comandone.

“The idea is if I’m timing my fertilizer application so that it’s in the right spot and amount needed by the plant, I’m going to have less emissions. It seems pretty straightforward, but in practice, there is little to no scientific proof that is the case.”

Comandone said soaring fertilizer costs are putting pressure on farmers to improve efficiency. “We can be skeptics about climate change, but if you are wasting fertilizer, you are literally volatizing your money into the air in the form of N2O.”

The research is taking place at the Smart Farm, which is a high-tech, living laboratory for crop, livestock and technology research spread over 3,000 acres. Olds College is at the forefront of precision agriculture technology to optimize fertilizer application, said Comandone.

“That’s why I’m here from Guelph. Olds College has an amazing group of researchers and equipment, and they can show if this technology works in the prairie region of Canada.”

The research involves applying two kinds of synthetic nitrogen fertilizers, with and without the use of variable-rate technology, for a total of four trial plots. Two plots were fertilized with a prescribed rate as recommended by an agrologist.

The other two plots received  higher and lower fertilizer rates according to the soil properties – typically a 15 to 30 per cent increase or decrease compared to the recommended rate – to measure the emissions impact of each.

To capture N2O emissions from the soil, Olds College is using automated LI-COR chambers on a canola crop. The devices consist of an automated chamber and a trace gas analyzer.

The chambers operate around the clock on a continuous cycle, sealing for about five minutes to capture gases from the soil, which are transferred to the analyzer. This provides continuous, high-resolution data on emissions of N2O, CO2 and water vapour.

This data is essential for the four-year national program, allowing researchers to analyze how emissions are impacted by practices like 4R nutrient stewardship (right rate, right time, right source and right place).

One of the goals is to use this information to develop robust models that can predict the carbon footprint of crop production across different growing seasons and weather conditions, said Comandone. “This year is canola. Next year is going to be wheat and the year after that, barley.”

However, the increasingly erratic weather and swings in temperature expected under climate change mean research will be needed for a much longer term, he said. “We cannot just do a three-year project at Olds College, make predictions and say the current situation is going to be the same 100 years from now.”