Slow-release urea fertilizer and nitrification inhibitors affect greenhouse gas emissions and population of soil microorganisms in a saturated soil

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:The mechanistic insight that N2O reduction is driven by AMO inhibition rather than microbial population shifts is valuable for soil microbiology and GHG modeling.

🏢実務担当者:Farmers and fertilizer companies can consider zeolite+DCD formulations to reduce N2O emissions from flooded fields, though field validation is needed.

🏛政策担当者:This supports including DCD in national GHG mitigation strategies for agriculture, but cost-benefit analysis and field trials are required.

The application of urea-based fertilizers in water-saturated soils represents a significant source of greenhouse gas (GHG) emissions, particularly nitrous oxide (N2O). This study evaluated the effects of zeolite-based slow-release urea combined with nitrification inhibitors on methane (CH4), carbon dioxide (CO2), and N2O emissions, as well as nitrogen transformation and soil microbial populations under saturated conditions. A 49-day laboratory incubation experiment was conducted using five treatments: control (no nitrogen), granulated urea (U), urea + zeolite (UZ), urea + zeolite + neem (UZN), and urea + zeolite + dicyandiamide (UZD). Methane emissions declined rapidly after 14 days and remained low across all treatments, indicating dominant methane oxidation under saturated conditions. Zeolite-amended treatments increased CO2 emissions, likely due to enhanced microbial respiration. Notably, the UZD treatment significantly reduced N2O emissions compared to other urea treatments, while maintaining higher ammonium (NH4⁺) and lower nitrate (NO3⁻) concentrations throughout the incubation period. The reduction in N2O emissions was not associated with changes in nitrite-oxidizing bacterial populations but rather with inhibition of ammonia monooxygenase (AMO), thereby suppressing nitrification and reduced substrate availability for N2O emissions. These findings indicate that process-based controls on nitrogen transformation are more critical than microbial population size in regulating N2O emissions. In contrast, neem-based treatments showed less consistent mitigation effects. Overall, the results demonstrate that combining zeolite-based slow-release urea with dicyandiamide is an effective strategy for mitigating N2O emissions under saturated soil conditions. However, field-scale validation is required to confirm these findings under natural agricultural conditions.

• crossref https://doi.org/10.25252/se/2026/243238first seen 2026-06-30 05:53:20