New Discovery Could Cut Agricultural Nitrous Oxide Emissions by One-Third

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• A recent breakthrough in agricultural research has the potential to reduce nitrous oxide emissions by one-third, significantly lowering the environmental impact of farming practices.
• This discovery involves innovative methods or technologies that can curtail the release of nitrous oxide, a potent greenhouse gas, from soil and fertiliser applications.
• Implementing this new approach could enhance sustainability in agriculture, contributing to global efforts to combat climate change and improve air quality.
• The reduction in nitrous oxide emissions could also lead to improved soil health and increased efficiency in nutrient use, benefiting both farmers and the environment.

Nitrogen fertilization, essential for plant growth, has long been a major source of the potent greenhouse gas nitrous oxide (N₂O) from agricultural soils. These emissions, contributing significantly to agricultural greenhouse gas output, were considered unavoidable.

However, an international research team led by NMBU has found a breakthrough solution. They identified bacteria that can “consume” nitrous oxide in the soil, preventing its release into the atmosphere. This method could potentially reduce Europe’s agricultural N₂O emissions by one-third.

Productive agriculture relies heavily on nitrogenous fertilizer, a technology pioneered by Fritz Haber over 120 years ago. Despite its benefits for global food production, fertilization also stimulates soil microorganisms that produce N₂O, a greenhouse gas with a global warming potential 300 times greater than CO₂.

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Globally, agriculture is the primary source of atmospheric nitrous oxide,” explains Wilfried Winiwarter, a co-author of the study and senior researcher at IIASA. “Reducing these emissions is challenging due to the complex regulation of soil bacteria.”

For over 20 years, NMBU researchers have studied soil microorganisms and their conversion of nitrogen under hypoxic conditions. When fertilization and rainfall create hypoxic soil environments, microbes switch from oxygen to nitrate for energy, producing N₂O in the process.

The team’s innovative research included robotic solutions to measure real-time N₂O emissions. They discovered a type of bacteria that doesn’t produce nitrous oxide but instead converts it to harmless nitrogen gas (N₂).

“If we cultivate these microbes in organic waste used as fertilizer, we can significantly reduce N₂O emissions,” says Lars Bakken, lead author of the study and NMBU professor. Finding the right bacteria was challenging, requiring strains that thrive in organic waste and soil, and persist throughout the growing season.

The researchers are now expanding their search for N₂O-consuming bacteria to be tested in various organic waste types worldwide. Their goal is to identify a diverse range of bacteria that can operate effectively in different soils and fertilizer mixtures, providing a robust solution to reduce agricultural nitrous oxide emissions.