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| Titel |
Life-cycle evaluation of nitrogen-use in rice-farming systems: implications for economically-optimal nitrogen rates |
| VerfasserIn |
Y. Xia, X. Yan |
| 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 ; 8, no. 11 ; Nr. 8, no. 11 (2011-11-07), S.3159-3168 |
| Datensatznummer |
250006193
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| Publikation (Nr.) |
 copernicus.org/bg-8-3159-2011.pdf |
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| Zusammenfassung |
| Nitrogen (N) fertilizer plays an important role in agricultural systems in
terms of food yield. However, N application rates (NARs) are often
overestimated over the rice (Oryza sativa L.) growing season in the Taihu Lake region of
China. This is largely because negative externalities are not entirely
included when evaluating economically-optimal nitrogen rate (EONR), such as
only individual N losses are taken into account, or the inventory flows of
reactive N have been limited solely to the farming process when evaluating
environmental and economic effects of N fertilizer. This study integrates
important material and energy flows resulting from N use into a rice
agricultural inventory that constitutes the hub of the life-cycle assessment
(LCA) method. An economic evaluation is used to determine an environmental
and economic NAR for the Taihu Lake region. The analysis reveals that
production and exploitation processes consume the largest proportion of
resources, accounting for 77.2 % and 22.3 % of total resources,
respectively. Regarding environmental impact, global warming creates the
highest cost with contributions stemming mostly from fertilizer production
and farming processes. Farming process incurs the biggest environmental
impact of the three environmental impact categories considered, whereas
transportation has a much smaller effect. When taking account of resource
consumption and environmental cost, the marginal benefit of 1 kg rice would
decrease from 2.4 to only 1.05 yuan. Accordingly, our current EONR has been
evaluated at 187 kg N ha−1 for a single rice-growing season. This could
enhance profitability, as well as reduce the N losses associated with rice
growing. |
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