IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 148 Soil Organic Matter, Caustobiolites, and Biochar Thursday, 27 August 2026 / Hall B SL73 Long-Term N Fertilization Altered Viral Community Composition and Increased Functional Potentials of Phosphorus Cycling by Causing Soil Acidification Shuxun Cheng1, Scott X. Chang2, Jianming Xu3, Zhongmin Dai4 1 Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China, sxcheng@zju.edu.cn 2 Department of Renewable Resources, University of Alberta, Edmonton, Alberta Canada T6G 2E3 3 Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China 4 Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China Viruses are pivotal agents in prokaryotic population dynamics and nutrient cycling [1]. Nevertheless, the effects of long-term nitrogen (N) fertilization on viral communities and their functional genes involved in phosphorus (P) cycling remain poorly characterized in agricultural ecosystems. Here, we investigated viral communities and P-cycling gene abundances across three long-term (>30 years) agroecosystem experiments subjected to N fertilization. Our results demonstrate that long-term N fertilization significantly altered viral community structure, increasing viral abundance and lysogenic prevalence, while enriching viral taxa such as Uroviricota. Soil acidification was identified as the primary driver of these viral community shifts, exceeding the influence of N availability. Furthermore, although prokaryotic functional genes involved in P solubilization and uptake declined under N fertilization, viral functional genes related to P-cycling were markedly enhanced, a response strongly correlated with acidification. These patterns suggest that viruses may exert a potential influence on prokaryotic P-cycling functions in acidified soil. Our findings highlight the critical role of viruses in sustaining soil P-cycling and underscore how long-term N fertilization, via soil acidification, regulates viral communities and their ecological functions in agroecosystems. References 1. Curtis A. Suttle, Nature Microbiology 1 (2016) 16205. Acknowledgement This study was supported by the National Key Research and Development Program of China (2023YFD1501700), the National Science Foundation of China (42577323), and Fundamental Research Funds for the Central Universities in China.
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