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Effects of nitrogen addition on soil methane uptake in global forest biomes.
- Source :
- Environmental Pollution; Sep2020, Vol. 264, pN.PAG-N.PAG, 1p
- Publication Year :
- 2020
-
Abstract
- Nitrogen (N) deposition has been conventionally thought to decrease forest soil methane (CH 4) uptake, while the biome specific and dose dependent effect is poorly understood. Based on a meta-analysis of 63 N addition trials from 7 boreal forests, 8 temperate forests, 13 subtropical and 4 tropical forests, we evaluated the effects of N addition on soil CH 4 uptake fluxes across global forest biomes. When combining all N addition levels, soil CH 4 uptake was insignificantly decreased by 7% in boreal forests, while N addition significantly decreased soil CH 4 uptake by 39% in temperate forests and by 21% in subtropical and tropical forests, respectively. Meta-regression analyses, however, indicated a shift from a positive to a negative effect on soil CH 4 uptake with increasing N additions both in boreal forests (threshold = 48 kg N ha<superscript>−1</superscript> yr<superscript>−1</superscript>) and temperate forests (threshold = 27 kg N ha<superscript>−1</superscript> yr<superscript>−1</superscript>), while no such shift was found in subtropical and tropical forests. Considering that current N deposition to most boreal and temperate forests is below the abovementioned thresholds, N deposition likely exerts a positive to neutral effect on soil CH 4 uptake in both forest biomes. Our results provide new insights on the biome specific and dose dependent effect of N addition on soil CH 4 sink in global forests and suggest that the current understanding that N deposition decreases forest soil CH 4 uptake is flawed by high levels of experimental N addition. Image 1 • The effects of N addition on soil CH 4 flux were evaluated in global forest biomes. • The effect of N addition was biome specific and dose dependent. • A shift from a positive to negative effect occurred with increasing N additions in boreal and temperate forests. • No shift of effect occurred with increasing N additions in subtropical and tropical forests. • Previous meta-analyses are likely flawed by high-level N additions. A meta-analysis indicates a biome specific and dose dependent effect of N addition on soil CH 4 sink in global forests and suggests that the current understanding that N deposition reduces forest soil CH 4 uptake is flawed by high levels of experimental N addition. [ABSTRACT FROM AUTHOR]
- Subjects :
- NITROGEN in soils
TEMPERATE forests
TROPICAL forests
BIOMES
TAIGAS
FOREST soils
Subjects
Details
- Language :
- English
- ISSN :
- 02697491
- Volume :
- 264
- Database :
- Supplemental Index
- Journal :
- Environmental Pollution
- Publication Type :
- Academic Journal
- Accession number :
- 143658473
- Full Text :
- https://doi.org/10.1016/j.envpol.2020.114751