Nitrogen fertilizer has helped transform modern agriculture, making abundant harvests possible across the globe. But the same nutrient that feeds crops can also escape into the atmosphere in two damaging forms: nitrous oxide, a powerful greenhouse gas, and ammonia, a reactive pollutant that contributes to fine-particle pollution and ecosystem degradation. A new study by Li, Yao, Han and colleagues, published in Nature Communications, points to a strategy that could reduce both emissions at once—not by simply applying less nitrogen, but by coordinating the biological processes that move nitrogen through soil.
The research, titled “Synchronizing nitrogen cycling processes reduces agricultural nitrous oxide and ammonia emissions,” focuses on a central problem in fertilizer management: nitrogen does not remain in one chemical form for long. In soil, ammonium can be converted by microbes into nitrite and nitrate through nitrification. Nitrate may then be absorbed by plants, washed away, or transformed through denitrification, a microbial process that can ultimately return nitrogen to the atmosphere as harmless nitrogen gas. When these transformations become poorly synchronized, nitrogen can accumulate in vulnerable forms, creating opportunities for ammonia volatilization and nitrous oxide production.
Ammonia emissions typically begin when ammonium in fertilizer or soil is converted into gaseous ammonia, particularly under conditions of high pH, warm temperatures, wind, or limited incorporation into the soil. Nitrous oxide, meanwhile, is commonly released during nitrification and denitrification, especially when soils alternate between oxygen-rich and oxygen-poor conditions. These processes are tightly linked: the chemical products of one microbial pathway often become the raw material for another. The study’s central insight is that reducing emissions may depend on controlling the timing and balance of these pathways rather than treating each pollutant as an isolated problem.
That concept is important because efforts to curb ammonia and nitrous oxide can sometimes pull in different directions. Measures that slow one nitrogen transformation may unintentionally increase the residence time of another nitrogen compound, allowing it to escape in a different form. For example, nitrogen that is not rapidly taken up by crops may remain as ammonium, increasing the risk of ammonia loss, or be converted into nitrate that can fuel denitrification and nitrous oxide formation. Synchronization, in this context, means aligning fertilizer availability, microbial activity, soil conditions, and crop demand so that nitrogen moves efficiently toward plant uptake or complete conversion to atmospheric nitrogen.
The researchers describe nitrogen cycling as a connected system rather than a sequence of independent reactions. Microorganisms carry out the biochemical steps, but their activity is shaped by moisture, oxygen availability, temperature, acidity, carbon supply, and the amount and timing of fertilizer. A sudden surge of ammonium can overwhelm plant demand and stimulate microbial transformations. Excessive wetness can restrict oxygen and create denitrification hotspots, while rapidly drying soil can generate abrupt shifts in microbial metabolism. By reducing these mismatches, synchronized management can limit the accumulation of nitrogen intermediates associated with emissions.
The implications extend beyond climate policy. Nitrous oxide is long-lived in the atmosphere and is also the most important ozone-depleting substance emitted by human activity. Ammonia, although not a greenhouse gas in the same direct sense, reacts in the atmosphere with acidic compounds to form fine particulate matter that can harm human health. It can also be deposited far from farms, enriching lakes, rivers, forests, and other ecosystems with excess nitrogen. Cutting both gases would therefore address several environmental pressures simultaneously: climate warming, air pollution, nutrient over-enrichment, and the inefficient use of fertilizer.
What makes the study particularly compelling is its shift in emphasis from reduction to coordination. Farmers and policymakers often focus on the amount of nitrogen applied, but emissions also depend on when, where, and in what form that nitrogen enters the soil. Management approaches consistent with the study’s findings could include matching applications more closely to crop demand, avoiding fertilizer placement before heavy rainfall, maintaining conditions that support plant uptake, and preventing prolonged periods in which ammonium or nitrate accumulates. The precise combination will vary by crop, climate, soil type, and production system, but the underlying principle is broadly applicable: nitrogen should move through the soil rapidly enough to be useful, but not so abruptly that microbes and plants fall out of step.
The findings also highlight why agricultural emissions are difficult to measure and control. Nitrous oxide release can occur in short-lived bursts from small areas, particularly after fertilization or rainfall. Ammonia losses can change within hours as temperature, wind, soil acidity, and fertilizer chemistry shift. A field may therefore appear efficient during one measurement period and highly emissive during another. Synchronizing nitrogen cycling could reduce these episodic losses by making the system less prone to sudden chemical imbalances, although successful implementation will require monitoring tools and management practices adapted to local conditions.
The study arrives as agriculture faces a difficult challenge: producing more food while reducing its environmental footprint. Nitrogen remains indispensable, and eliminating fertilizer is neither realistic nor desirable in many food systems. The more promising path is to make every unit of nitrogen work harder for crops and less often escape into the atmosphere. By showing that the timing and interaction of soil processes matter as much as fertilizer quantity, Li, Yao, Han and their colleagues offer a fresh framework for tackling agricultural pollution. The message is simple but scientifically powerful: when nitrogen cycling processes operate in sync, farms may be able to protect yields while releasing less of two of agriculture’s most consequential atmospheric pollutants.
Subject of Research: Agricultural nitrogen cycling and the reduction of nitrous oxide and ammonia emissions
Article Title: Synchronizing nitrogen cycling processes reduces agricultural nitrous oxide and ammonia emissions
Article References: Li, M., Yao, Y., Han, B. et al. “Synchronizing nitrogen cycling processes reduces agricultural nitrous oxide and ammonia emissions.” Nature Communications (2026). https://doi.org/10.1038/s41467-026-76977-4
Image Credits: AI Generated
DOI: 10.1038/s41467-026-76977-4
Keywords: nitrogen cycling, agriculture, nitrous oxide, ammonia emissions, fertilizer management, nitrification, denitrification, climate change, air pollution, soil microbiology
