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Recently, a research team in the Hefei Institutes of ÌÇÐÄÊÓƵical Science of the Chinese Academy of Sciences has revealed that one-time nitrogen (N) application, a labor-saving practice favored by many farmers, increases both soil and canopy ammonia (NH₃) emissions in maize fields, while reducing grain yield and nitrogen use efficiency.

The research results were in Atmospheric Pollution Research.

The findings are based on a two-year field experiment in Hefei, China.

In the study, the researchers compared plots that received no nitrogen, plots that received all nitrogen as a single early dose, and plots where the nitrogen was split between an early application and a later topdressing. By using portable NH₃ detectors, they measured how much ammonia escaped from the soil and from the maize leaves, which together represent the total field NH₃ loss.

Compared to the split nitrogen application, the one-time nitrogen application led to higher canopy and soil ammonia emissions, while lowering both grain yield and nitrogen recovery efficiency.

"High soil ammonium (NH₄⁺) concentration and low soil moisture in one-time N application drove more soil NH₃ loss, while large leaf area and high leaf apoplast NH₄⁺ concentration boosted canopy emissions," explained Dr. Yang Yang, a member of the team, "Our results highlight that split N application is a more sustainable choice with lower NH₃ emissions and better maize productivity."

The findings provide practical insights for optimizing fertilizer use and reducing air pollution from agriculture.