Soil pH as the chief modifier for regional nitrous oxide emissions: New evidence and implications for global estimates and mitigation.
Glob Chang Biol
; 24(2): e617-e626, 2018 02.
Article
em En
| MEDLINE
| ID: mdl-29171128
ABSTRACT
Nitrous oxide (N2 O) is a greenhouse gas that also plays the primary role in stratospheric ozone depletion. The use of nitrogen fertilizers is known as the major reason for atmospheric N2 O increase. Empirical bottom-up models therefore estimate agricultural N2 O inventories using N loading as the sole predictor, disregarding the regional heterogeneities in soil inherent response to external N loading. Several environmental factors have been found to influence the response in soil N2 O emission to N fertilization, but their interdependence and relative importance have not been addressed properly. Here, we show that soil pH is the chief factor explaining regional disparities in N2 O emission, using a global meta-analysis of 1,104 field measurements. The emission factor (EF) of N2 O increases significantly (p < .001) with soil pH decrease. The default EF value of 1.0%, according to IPCC (Intergovernmental Panel on Climate Change) for agricultural soils, occurs at soil pH 6.76. Moreover, changes in EF with N fertilization (i.e. ΔEF) is also negatively correlated (p < .001) with soil pH. This indicates that N2 O emission in acidic soils is more sensitive to changing N fertilization than that in alkaline soils. Incorporating our findings into bottom-up models has significant consequences for regional and global N2 O emission inventories and reconciling them with those from top-down models. Moreover, our results allow region-specific development of tailor-made N2 O mitigation measures in agriculture.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Solo
/
Mudança Climática
/
Óxido Nitroso
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Glob Chang Biol
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
China