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| Titel |
Introducing non-flooded crops in rice-dominated landscapes: Impact on carbon, nitrogen and water budgets |
| VerfasserIn |
Frank Jauker, Reiner Wassmann, Wulf Amelung, Lutz Breuer, Klaus Butterbach-Bahl, Ralf Conrad, Klemens Ekschmitt, Heiner Goldbach, Yao He, Katharina John, Ralf Kiese, David Kraus, Barbara Reinhold-Hurek, Jan Siemens, Sebastian Weller, Volkmar Wolters |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082090
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| Zusammenfassung |
| Rice production consumes about 30% of all freshwater used worldwide and 45% in Asia.
Turning away from permanently flooded rice cropping systems for mitigating future water
scarcity and reducing methane emissions, however, will alter a variety of ecosystem services
with potential adverse effects to both the environment and agricultural production. Moreover,
implementing systems that alternate between flooded and non-flooded crops increases the
risk of disruptive effects.
The multi-disciplinary DFG research unit ICON aims at exploring and quantifying the
ecological consequences of altered water regimes (flooded vs. non-flooded), crop
diversification (irrigated rice vs. aerobic rice vs. maize), and different fertilization strategies
(conventional, site-specific, and zero N fertilization). ICON particularly focuses on the
biogeochemical cycling of carbon and nitrogen, green-house gas (GHG) emissions,
water balance, soil biotic processes and other important ecosystem services. The
overarching goal is to provide the basic process understanding that is necessary for
balancing the revenues and environmental impacts of high-yield rice cropping systems
while maintaining their vital ecosystem services. To this aim, a large-scale field
experiment has been established at the experimental farm of the International Rice
Research Institute (IRRI, Philippines). Ultimately, the experimental results are
analyzed in the context of management scenarios by an integrated modeling of
crop development (ORYZA), carbon and nitrogen cycling (MoBiLE-DNDC), and
water fluxes (CMF), providing the basis for developing pathways to a conversion of
rice-based systems towards higher yield potentials under minimized environmental
impacts.
In our presentation, we demonstrate the set-up of the controlled large-scale field
experiment for simultaneous assessment of carbon and nitrogen fluxes and water budgets. We
show and discuss first results for:
- Quantification and assessment of the net-fluxes of CH4, N2O and CO2 from rice-rice
and rice-maize rotations. The conversion of flooded to non-flooded cropping systems resulted
in pollution swapping of greenhouse gas emissions, shifting from CH4 under wet conditions
to N2O under dry conditions.
- Quantification and assessment of water budgets and nutrient loss in rice-rice and
rice-maize rotations. Switching from rice-rice dominated growing systems to upland rice or
maize-rice cropping systems resulted in reduced water use efficiency and increased nitrogen
loss.
- Quantification and assessment of soil functions affected by soil fauna community
structure in flooded and non-flooded cropping rotations. In contrast to temperate soils,
earthworms reduced the peaks of microbial C and N decomposition depending on soil water
content. |
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