Recent research conducted by Aarhus University and the University of Padua has unveiled critical insights into the impact of soil compression from heavy agricultural machinery on nitrous oxide production. The study, published on December 3, 2024, reveals that soil compression alters the size and connectivity of soil pores, which are essential for air and water movement.
Mansonia Pulido-Moncada from Aarhus University's Agroecology Institute explains, "Our findings indicate that soil compression at varying depths diminishes both the quantity and size of soil pores, leading to less oxygen absorption. Under wet conditions with reduced oxygen, nitrous oxide is produced more readily, while also affecting how this gas moves and is released into the atmosphere." This dual effect presents a challenge: while compression can trap some nitrous oxide, it also creates pockets that may lead to increased emissions when the soil drains.
Utilizing advanced X-ray imaging techniques known as microtomography, researchers analyzed the pore structure of the soil. They found that pore connectivity serves as a key indicator of nitrous oxide movement. "In a non-compressed soil sample, a vast network of connected pores facilitates the desired transport of gases and water, especially after rainfall. In compressed soil, however, there are fewer, smaller, and disconnected pores, complicating gas movement," Pulido-Moncada notes.
For farmers, these findings underscore the importance of preventing soil compression. Implementing practices such as reduced tillage, cover cropping, and proper machinery management can help maintain soil structure and functionality. Pulido-Moncada emphasizes, "There are numerous compelling reasons to avoid soil compression—not only to mitigate nitrous oxide emissions but also to enhance soil health, which in turn boosts crop yields and human well-being. Even small adjustments in agricultural practices can significantly impact the environment."