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Nitrogen deposition reduces methane uptake in both the growing and non-growing season in an alpine meadow.
- Source :
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Science of the Total Environment . Dec2020, Vol. 747, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
-
Abstract
- Nitrogen (N) deposition-induced N input in alpine meadow soils may affect the soil exchange of methane (CH 4) with the atmosphere. The quantities and spatiotemporal variation in CH 4 uptake remain largely unknown for this ecosystem on a global scale. Previous studies regarding CH 4 flux have mainly focused on the growing season in alpine meadows. Thus, the impact of N deposition on the non-growing season uptake of CH 4 is unknown. In this study, we investigated the effects of N deposition on CH 4 uptake during both the growing and non-growing seasons in an alpine meadow on the central Qinghai-Tibet Plateau (QTP). The CH 4 fluxes were measured using static chambers and gas chromatography in four N deposition treatment areas (Control; N7, 7 kg N ha−1 yr−1; N20, 20 kg N ha−1 yr−1; N40, 40 kg N ha−1 yr−1) from May 2015 to August 2018. Our results showed that alpine meadow soils acted as CH 4 sinks throughout the year. N deposition significantly decreased CH 4 uptake fluxes (P < 0.05) and the annual mean CH 4 uptake fluxes declined at N deposition levels of 7, 20, and 40 kg N ha−1 yr−1 by 12.3%, 14.4%, and 20.5%, respectively, compared with that of the control. Annual CH 4 uptake was significantly correlated with total annual precipitation, mean annual air temperature, and N deposition rate. Annual cumulative CH 4 uptake in the four treatments across 3 years was 75.1 mg C m−2, where approximately 40% of the total annual CH 4 uptake occurred during the non-growing season. Our results showed that CH 4 uptake in the non-growing season cannot be ignored when estimating annual uptake of CH 4 because of the large CH 4 uptake during the non-growing season in the alpine meadow on the QTP under N deposition conditions. Contribution of different seasons to the annual cumulative CH 4 uptake in an alpine meadow on the Qinghai-Tibet Plateau. N7, N20, and N40 represent 7, 20, and 40 kg N ha−1 yr−1 nitrogen deposition, respectively. GSC = growing seasonal cumulative CH 4 uptake, NGSC = non-growing seasonal cumulative CH 4 uptake, AC = annual cumulative CH 4 uptake. Unlabelled Image • We investigated effects of N deposition on CH4 uptake in an alpine meadow on QTP. • N deposition significantly decreased CH4 uptake. • CH4 uptake in non-growing season accounted for about 40% of annual CH4 uptake. • CH 4 uptake was regulated by precipitation, air temperature and N deposition rate. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00489697
- Volume :
- 747
- Database :
- Academic Search Index
- Journal :
- Science of the Total Environment
- Publication Type :
- Academic Journal
- Accession number :
- 146398461
- Full Text :
- https://doi.org/10.1016/j.scitotenv.2020.141315