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| Titel |
Net global warming potential and greenhouse gas intensity in a double-cropping cereal rotation as affected by nitrogen and straw management |
| VerfasserIn |
T. Huang, B. Gao, P. Christie, X. Ju |
| 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 ; 10, no. 12 ; Nr. 10, no. 12 (2013-12-04), S.7897-7911 |
| Datensatznummer |
250085456
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| Publikation (Nr.) |
 copernicus.org/bg-10-7897-2013.pdf |
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| Zusammenfassung |
| The effects of nitrogen and straw management on global warming potential
(GWP) and greenhouse gas intensity (GHGI) in a winter wheat–summer maize
double-cropping system on the North China Plain were investigated. We
measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and
GHGI by calculating the net exchange of CO2 equivalent
(CO2-eq) from greenhouse gas emissions, agricultural inputs and
management practices, as well as changes in soil organic carbon (SOC), based on a
long-term field experiment established in 2006. The field experiment includes
six treatments with three fertilizer N levels (zero N (control), optimum and
conventional N) and straw removal (i.e. N0, Nopt and
Ncon) or return (i.e. SN0, SNopt and
SNcon). Optimum N management (Nopt, SNopt)
saved roughly half of the fertilizer N compared to conventional agricultural
practice (Ncon, SNcon), with no significant effect on
grain yields. Annual mean N2O emissions reached 3.90 kg
N2O-N ha−1 in Ncon and SNcon, and N2O
emissions were reduced by 46.9% by optimizing N management of
Nopt and SNopt. Straw return increased annual mean
N2O emissions by 27.9%. Annual SOC sequestration was 0.40–1.44 Mg
C ha−1 yr−1 in plots with N application and/or straw return.
Compared to the conventional N treatments the optimum N treatments reduced
NGWP by 51%, comprising 25% from decreasing N2O emissions and
75% from reducing N fertilizer application rates. Straw return
treatments reduced NGWP by 30% compared to no straw return because the
GWP from increments of SOC offset the GWP from higher emissions of N2O,
N fertilizer and fuel after straw return. The GHGI trends from the different
nitrogen and straw management practices were similar to the NGWP. In
conclusion, optimum N and straw return significantly reduced NGWP and GHGI
and concomitantly achieved relatively high grain yields in this important
winter wheat–summer maize double-cropping system. |
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