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| Titel |
Quantifying methane emissions from rice fields in the Taihu Lake region, China by coupling a detailed soil database with biogeochemical model |
| VerfasserIn |
L. Zhang, D. Yu, X. Shi, D. Weindorf, L. Zhao, W. Ding, H. Wang, J. Pan, C. Li |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 5 ; Nr. 6, no. 5 (2009-05-06), S.739-749 |
| Datensatznummer |
250003739
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| Publikation (Nr.) |
 copernicus.org/bg-6-739-2009.pdf |
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| Zusammenfassung |
| As China has approximately 22% of the world's rice
paddies, the regional quantification of CH4 emissions from these
paddies is important in determining their contribution to the global
greenhouse gas effect. This paper reports the use of a biogeochemical model
(DeNitrification and DeComposition or DNDC) for quantifying CH4
emissions from rice fields in the Taihu Lake region of China. For this
application, the DNDC model was linked to a 1:50 000 soil database derived
from 1107 paddy soil profiles compiled during the Second National Soil
Survey of China in the 1980s–1990s. The simulated results showed that the
2.3 Mha of paddy rice fields in the Taihu Lake region emitted the equivalent
of 5.7 Tg C from 1982–2000, with the average CH4 flux ranging from 114
to 138 kg C ha−1 y−1. As for soil subgroups, the highest emission
rate (660 kg C ha−1 y−1) was linked to gleyed paddy soils
accounting for about 4.4% of the total area of paddy soils. The lowest
emission rate (91 kg C ha−1 y−1) was associated with degleyed
paddy soils accounting for about 18% of the total area of paddy soils.
The most common soil in the area was hydromorphic paddy soils, which
accounted for about 53% of the total area of paddy soils with a CH4
flux of 106 kg C ha−1 y−1. On a regional basis, the annual
averaged CH4 flux in the Taihu Lake plain soil region and alluvial
plain soil region were higher than that in the low mountainous and hilly
soil region and the polder soil region. The model simulation was conducted
with two databases using polygons or counties as the basic units. The
county-based database contained soil information coarser than the polygon
system built based on the 1:50 000 soil database. The modeled results with
the two databases found similar spatial patterns of CH4 emissions in
the Taihu Lake region. However, discrepancies exist between the results from the
two methods. The total CH4 emissions generated from the polygon-based
database is 2.6 times the minimum CH4 emissions generated from the
county-based database, and is 0.98 times the maximum CH4 emissions
generated from the county-based database. The average value of the relative
deviation ranged from −20% to 98% for most counties, which indicates
that a more precise soil database is necessary to better simulate CH4
emissions from rice fields in the Taihu Lake region using the DNDC model. |
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