Project: Sustainable and environmental friendly rice cultivation systems in Europe
In Europe, rice (467 000 ha) is gown under permanently flooded (PF) conditions 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
increased demands for rice both from within Europe (net deficit of 0.86 Mt) and from
overseas. Rice yields under existing production practices are therefore threatened by
scarcer water availability. In addition, PF rice fields emit greenhouse gases (GHG), such as
methane (CH4), that have a strong global warming potential. Alternate wetting and drying
(AWD) is a system in which irrigation is applied to obtain 2 to 5 cm of field water depth,
and then turned off. After a short period (normally 2 to 7 days), when the field has dried
out, water is re-applied. Preliminary studies suggest that AWD can reduce water use by up
to 30 %, with no net loss in yield provided varieties well adapted to AWD are used, while
CH4 emissions can be reduced by up to 48 %. However, uncertainties still remain as to the
impacts of AWDS on GHG fluxes (e.g. CO2, N2O) and plant-mutualist and plant-pest
interactions, which may influence the overall efficacy and viability of this new system.
Thus, while AWD represents a potentially exciting alternative water management strategy
for European rice production, a more complete agronomic, ecological and biogeochemical
assessment of AWD is required to evaluate the benefits of the system. To close these
critical knowledge gaps, GreenRice aims to test AWDS in Italy, Spain and France, in
regions that are representative of the diversity of European rice growing areas, notably in
deltaic areas where rice systems and natural protected wetlands are interdependent. We
will evaluate the agronomic and environmental consequences of shifting from a PF to an
AWD system, focusing on rice yields, water consumption, soil salinization,
plant-soil-microbial interactions and GHG dynamics. We will identify varieties that maintain
their productivity under AWDS through whole genome association mapping of a large
panel of temperate varieties, using genomic selection to predict the values of additional
breeding lines. We will investigate traits determining adaptation to AWDS, such as root
development, AM colonisation, salt tolerance and resistance to nematodes; and the role of
AM symbiosis in alleviating the impacts of biotic stress. An extensive gene expression
study will identify the root types and genes important in transport process and the degree
to which they are affected by AWDS. The role of plant functional traits and the soil
microbial activity in modulating C, N and GHG fluxes will be investigated in both
field-based and controlled environment studies. The results obtained will be disseminated
to local stakeholders (primarily farmers and natural park authorities) and to the scientific
community.
Project partner
