OMAFA: Cover crops and nitrous oxide emissions

Aug 28, 2024

Cover crops help build soil carbon, reduce erosion, and can offset crop nitrogen fertilizer requirements. But when it comes to nitrous oxide (N₂O) – a greenhouse gas that contributes about half the total warming effect from agriculture in Canada – there is a question mark surrounding their benefit.

The primary driver of nitrous oxide emissions from agricultural soils is denitrification, which is promoted by wet soils, ample available mineral nitrogen (e.g. nitrate), the presence of carbon sources and freeze-thaw cycles. Cover crops influence each of these conditions. A 2014 meta-analysis found that cover crops decreased N₂O emissions in 40 per cent of studies and increased them in the other 60 per cent.

The following factors determined cover crop effects on emissions:

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Video: Dr. Emerson Nafziger: Nitrogen Fertilizer Rates for Corn

The Crop Science Podcast Show, Dr. Emerson Nafziger from the University of Illinois breaks down decades of nitrogen research. From the evolution of N rate guidelines to how soil health and hybrid genetics influence nitrogen use efficiency, this conversation unpacks the science behind smarter fertilization. Improving how we set nitrogen fertilizer rates for rainfed corn is a key focus. Discover why the MRTN model matters more than ever, and how shifting mindsets and better data can boost yields and environmental outcomes. Tune in now on all major platforms!

"The nitrogen that comes from soil mineralization is the first nitrogen the plant sees, and its role is underestimated."

Meet the guest:

Dr. Emerson Nafziger is Professor Emeritus of Crop Sciences at the University of Illinois at Urbana-Champaign, with degrees in agronomy from Ohio State, Purdue, and Illinois. His research has focused on nitrogen rate strategies and crop productivity. He co-developed the Maximum Return to Nitrogen (MRTN) model, which is widely used across the Midwest. His research spans N response trials, hybrid interactions, crop rotation effects, and yield stability.