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| Titel |
Preliminary results on yield and CO2 fluxes when using alternate wetting and drying on different varieties of European rice |
| VerfasserIn |
Viktoria Oliver, Stefano Monaco, Andrea Volante, Nicole Cochrane, Massimo Gennaro, Gabriele Orasen, Giampiero Valè, Adam Price, Yit Arn Teh |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129068
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| Publikation (Nr.) |
 EGU/EGU2016-9131.pdf |
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| Zusammenfassung |
| In Europe, rice is grown (467 000 ha) under permanently flooded conditions (PF) using
irrigation waters of major rivers. Climate change, which has led to a greater fluctuation in
river flows, is a major challenge to rice production systems, which depend on large and
consistent water supplies. This challenge will become more acute in the future,
with more frequent extreme weather (e.g. drought) predicted under climate change
and increased demands for rice. Alternate wetting and drying (AWD) is a system
in where irrigation is applied to obtain 2-5 cm of field water depth, after which
the soil is allowed to drain naturally to typically 15 cm below the surface before
re-wetting once more. Preliminary studies suggest that AWD can reduce water use
by up 30 %, with no net loss in yield but significantly reducing CH4 emissions.
However, uncertainties still remain as to the impacts of AWD on CO2 exchange,
N2O fluxes, and plant acclimation responses to a fluctuating water regime. For
example, CO2 emissions could potentially increase in AWD due to higher rates of soil
organic matter decomposition when the fields are drained. The work presented here
evaluated the impacts of AWD on the productivity and yield of twelve varieties of
European rice, whilst simultaneously measuring CO2 exchange, N2O fluxes, and plant
biomass allocation patterns under different treatment regimes. Field experiments
were conducted in the Piedmont region (northern Italy Po river plain) in a loamy
soil during the growing season of 2015 in a 2-factor paired plot design, with water
treatment (AWD, PF) and variety (12 European varieties) as factors (n=4 per variety
per treatment). The varieties chosen were commercially important cultivars from
across the rice growing regions of Europe (6 Italian, 3 French, 3 Spanish). Light
and dark CO2 fluxes were measured six times over the growing season, using an
infra-red gas analyzer. Environmental variables (soil moisture, temperature, water table
depth, water potential, PAR) were collected concomitantly. Above and belowground
biomass were determined by destructively harvesting at the end of the growing season.
Belowground biomass was estimated by manually extracting roots from 30 cm
deep soil cores and aboveground biomass estimated by collecting and weighing
the rachis, grain and straw on a 1 metre linear section from every variety of rice.
Overall, there was no significant effect between AWD and PF systems on rough grain
production (863 and 822 g DM m−2) or straw yield (776 and 813 g DM m−2) for PF
and AWD, respectively. There was also no significant difference for net ecosystem
exchange (NEE) (-10.83 ± 1.10 and -9.71 ± 1.17 mg C m−2 s−1) or ecosystem
respiration (Re) (6.86 ± 0.63 and 6.26 ± 0.61 mg C m−2 s−1), with the exception of
one French variety (Gageron). This cultivar showed a significant increase in NEE
under AWD (PF = -13.61 ± 2.89 and AWD = -17.63 ± 5.33 mg C m−2 s−1). The
results from this study highlight that this novel water management strategy for
European rice can have multiple environmental benefits without sacrificing yield. |
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