Impact of plant protection product applications on soil microbial nitrogen cycle function not fully captured by gene quantification
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Author (Corporation)
Publication date
09.2025
Type of student thesis
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Type
01A - Journal article
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Parent work
Applied Soil Ecology
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Volume
213
Issue / Number
Pages / Duration
106297
Patent number
Publisher / Publishing institution
Elsevier
Place of publication / Event location
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Abstract
The widespread use of plant protection products (PPPs) in agriculture raises concerns about their long-term impact on soil health and nitrogen (N) cycling. Current regulatory assessments focus mostly on single active ingredients and microbial mineralisation, ignoring the complexities of formulated PPPs and their influence on microbial functions. We investigated the effects of realistic PPP application scenarios on soil N cycling using a controlled incubation experiment with increasing PPP intensities, measuring potential nitrification (PN), denitrifying enzyme activity (DEA), and N₂O reduction capacity (NRC), alongside molecular analyses of key microbial genes involved in N-cycling. Functional assays were more sensitive to PPP exposure than gene abundances, indicating severe disruptions to N cycling. Among measured processes, PN was the most PPP-sensitive, showing substantial reductions across treatments. DEA and NRC were also strongly inhibited, exhibiting complex temporal patterns. While gene abundances were less responsive, there were significant positive correlations between the gene abundance of archaeal and bacterial ammonia monooxygenase (amoA) and PN, as well as between nitrite reductase (nirK) and DEA. Our findings underscore the importance of updated risk assessments that integrate both molecular and functional indicators. We propose a tiered approach, using gene quantification as an initial screening tool, followed by functional assays to capture biologically relevant changes. Post-registration monitoring of PPP mixtures under field conditions is likewise essential to address cumulative and long-term impacts. Overall, this study highlights the vulnerability of soil N cycling to PPP exposure and provides a framework to enhance environmental risk assessments aimed at safeguarding soil ecosystem functions.
Keywords
Soil function, Formulated pesticide mixtures, Nitrogen cycling, Microbial ecotoxicology, Risk assessment, Bioindicators
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ISBN
ISSN
0929-1393
1873-0272
1873-0272
Language
English
Created during FHNW affiliation
Yes
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the complete publication
Open access category
Hybrid
License
Citation
Medici, L., Niklaus, P. A., Walder, F., & Langer, M. (2025). Impact of plant protection product applications on soil microbial nitrogen cycle function not fully captured by gene quantification. Applied Soil Ecology, 213, 106297. https://doi.org/10.1016/j.apsoil.2025.106297