Based on a recently published study from the University of Illinois Urbana-Champaign, researchers have uncovered key insights into how greenhouse gases—especially nitrous oxide—are released from farm soils. The findings reveal not only how unpredictable these emissions can be, but also how farming practices can help manage them.
Nitrous oxide is a powerful greenhouse gas, trapping nearly 300 times more heat in the atmosphere than carbon dioxide. It’s largely released when crops are given more nitrogen fertilizer than they can absorb. About 70% of human-caused nitrous oxide emissions come from agricultural soils, making it critical to find ways to reduce them.
To better understand how these emissions behave, the research team collected the most comprehensive dataset to date from commercial corn and soybean fields. Supported by the U.S. Department of Energy’s ARPA-E SMARTFARM program, they studied fields using different tillage systems—conventional, conservation, and no-till—over multiple growing seasons.
Gas sampling equipment was installed across a wide network of fields, and emissions were measured weekly or biweekly for two years. The results showed that carbon dioxide emissions were relatively stable across crops, locations, and years. This suggests that moderate sampling is sufficient for estimating overall carbon dioxide levels.
In contrast, nitrous oxide emissions were highly variable. Emission spikes—called hot spots and hot moments—were triggered by fertilizer applications, rainfall, and other conditions, and shifted unpredictably from place to place and week to week. This variability means that studies with limited sampling may have significantly misjudged true emission levels.
Even though nitrous oxide is hard to predict, the study confirmed that farm management matters. Continuous cornfields with conventional tillage produced the highest emissions due to heavy nitrogen use and soil disturbance. Soybean fields and those managed with conservation or no-till methods had much lower emissions.
These findings not only provide practical insights for farmers looking to reduce their environmental impact but also help improve the accuracy of climate models that rely on greenhouse gas data from agriculture.
