Using the Infer Community Assembly Mechanisms (iCAMP) framework, researchers show that this strategy rebalances the microbial guilds responsible for N₂O production and reduction, allowing soils to maintain high yield potential while emitting far less of this potent greenhouse gas. The manure-integrated treatment improved soil quality, enriched key N₂O-reducing microbes, and shifted ecological selection in favor of communities that naturally mitigate emissions.
Synthetic nitrogen fertilizers have become essential to meeting global food demand, yet their widespread use has created mounting environmental risks. A significant fraction of applied nitrogen escapes through leaching and volatilization, and agricultural soils now represent the largest human-driven source of N₂O—an extremely potent greenhouse gas. Microbial nitrification and denitrification processes control whether soils act as sources or sinks of N₂O, with different microbial guilds responsible for producing or reducing the gas. How fertilization regimes shape these communities depends on ecological assembly processes, which may be deterministic (environmental filtering) or stochastic (drift and dispersal). Due to these challenges, understanding how management strategies restructure microbial guilds is essential for developing sustainable nitrogen use.
A study (DOI:10.48130/nc-0025-0007) published in Nitrogen Cycling on 17 October 2025 by Zhujun Wang’s & Xiaotang Ju’s team, Hainan University, provides a clear, mechanism-based strategy for designing nitrogen management practices that meet productivity demands while reducing environmental harm.
In this study, the authors combined field measurements with multiple molecular and statistical approaches to unravel how long-term fertilizer regimes shape soil nitrogen (N) cycling. First, they compared basic soil properties, N pools, potential nitrification (PNR) and denitrification (PDR), and crop yield across four treatments (no N, optimum synthetic N, conventional synthetic N, and balanced manure plus synthetic N, Nbal + M). They then used qPCR to quantify key N-cycling functional genes and total bacterial abundance, Non-metric Multidimensional Scaling (NMDS) with PERMANOVA to test treatment effects on community structure, and Mantel tests to link microbial communities with soil properties and N₂O emissions. Finally, the iCAMP framework was applied to partition community assembly into deterministic (homogeneous/heterogeneous selection) and stochastic (drift and dispersal) processes for each functional guild. The measurements showed that Nbal + M produced the highest total N, soil organic carbon, and Olsen P, and significantly enhanced the soil quality index, PNR, PDR, and crop yield, while maintaining lower N₂O emissions than conventional N. qPCR revealed that bacterial amoA abundance was specifically boosted under conventional N, whereas manure integration strongly increased nosZ (nosZI and especially nosZII) gene abundances linked to N₂O reduction. NMDS and PERMANOVA indicated that fertilization significantly restructured bacterial, amoA, comammox, nirK, and nosZII communities, and Mantel tests identified N₂O fluxes, SOC, TN, Olsen P, PNR, and PDR as key factors correlated with these community patterns. iCAMP analysis further showed that total bacteria, AOA, and nosZI were dominated by stochastic processes, while AOB, comammox, nirK, nirS, and nosZII were mainly governed by deterministic homogeneous selection, with fertilization—and especially Nbal + M—shifting the balance of determinism and stochasticity in guild-specific ways that help explain contrasting N₂O emission outcomes.
Manure-integrated fertilization enhances soil quality, supports long-term nutrient retention, and decreases N₂O emissions by promoting deterministic selection for N₂O-reducing microbial guilds. This ecological steering moves beyond conventional nutrient replacement approaches, showing that sustainable agriculture can be achieved by intentionally cultivating a microbiome optimized for climate mitigation. The insights could directly inform fertilizer policy, carbon-neutral agriculture initiatives, and region-specific nutrient-management guidelines across major cropping systems.
###
References
DOI
10.48130/nc-0025-0007
Original Source URL
https://doi.org/10.48130/nc-0025-0007
Funding information
This work was supported by the National Natural Science Foundation of China (Grant No. U24A20625).
About Nitrogen Cycling
Nitrogen Cycling is a multidisciplinary platform for communicating advances in fundamental and applied research on the nitrogen cycle. It is dedicated to serving as an innovative, efficient, and professional platform for researchers in the field of nitrogen cycling worldwide to deliver findings from this rapidly expanding field of science.