Biotic and abiotic predictors of potential N2O emissions from denitrification in Irish grasslands soils: A national-scale field study
Date
2022-03-21
Journal Title
Journal ISSN
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Publisher
Elsevier
Abstract
Large-scale information regarding nitrous oxide (N2O) emissions is needed as an evidence base to underpin land
use policy and mitigation approaches. However, the highly variable rates of denitrification make the prediction
of N2O emission demanding. Here, we evaluated the role of abiotic and biotic factors on the potential denitrification
of Irish soils, in order to identify the key factors regulating potential N2O emissions at a large scale. To do
so, we collected 136 soil samples from 32 sites across Ireland, and characterised the soil physico-chemical
properties, the prokaryotic and fungal community composition, the abundance of N-cycling genes and evaluated
the soil potential nitrification, denitrification and end product N2O/(N2O + N2). We found large differences
in soil potential denitrification between sites (up to 41.5 mg N2O–N kg 1 soil day 1) with most of the emissions
released in the form of N2O rather than N2. Soils with highest potential nitrification rates also exhibited the
highest potential denitrification rates, and similar parameters were linked to both processes. The factors most
predictive of soil potential denitrification were soil physico-chemical properties and the prokaryotic community
composition. Soil phosphorus content was as important for predicting potential denitrification as was pH and
total nitrogen. Soil microbial community structure, rather than denitrifier abundance, was an important predictor
of the potential denitrification and the end-product N2O/(N2O + N2). The prokaryotic community
composition was more strongly associated with denitrification rates and the resulting end-products than fungal
communities. Increased relative abundance of the prokaryotic phyla Actinobacteriota and Crenarchaeota, were
positively correlated to complete denitrification. Altogether, these results lay the foundation for a better understanding
of the key factors regulating the potential denitrification in soils and identify important properties
that enhance prediction of the potential denitrification at larger scales.
Description
Publication history: Accepted - 18 March 2022; Published - 25 March 2022.
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Article
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Keywords
Denitrification, Nitrification, Functional N cycling Communities, Microbial community structure, Nitrous oxide, Managed grasslands
Citation
Deveautour, C., Rojas-Pinzon, P.A., Veloso, M., Rambaud, J., Duff, A.M., Wall, D., Carolan, R., Philippot, L., Richards, K.G., O’Flaherty, V. and Brennan, F. (2022) ‘Biotic and abiotic predictors of potential N2O emissions from denitrification in Irish grasslands soils: A national-scale field study’, Soil Biology and Biochemistry. Elsevier BV. doi:10.1016/j.soilbio.2022.108637.