Modifying water management for rice production
BUT
Rice is not just a vic1m of climate change,
it is also one of the causes
How methane is produced by irrigated rice
=> Rice fields account for 5 -20 % of all global methane sources
‘Closed Chamber‘ Method
Diurnal patterns
Pooled field data, Buendia et al. 1997
Relevance for CCAFS?
One of the Fund Council comments:
o Articulate potential contribution to development of global standards for measuring GHG emissions from agriculture
16 Jan 2009 7 Unit plot size: 5 x 5 m
Field stations of the Intenational Rice Research Institute (projects funded by US-EPA and UNDP/ GEF)
Irrigated Rainfed Deepwater
IRRI/ Los Banos
View of the field
chambers (for flooded/ non-flooded
condition)
Days after planting
Mid-season drainage
Field experiment at Hangzhou, China (Wassmann et al., 2000)
‘Site-Specific Nutrient Management’ (SSNM)
Applying nutrients as and when needed
Adjusting nutrient application to crop needs in given location and season
Leaf Color Chart
" downward flux – atmospheric CO2 taken up by the rice plant for photosynthesis
" upward flux – CO2 being released from ecosystem respiration
Modelling emissions using DNDC model (DeNitrification-DeComposition)
from Li et al. 2000
Inputs
SOIL Texture, pH, C and N content
CLIMATE Temp., rainfall
MANAGEMENT N inputs, tillage, irrigation etc.
Outputs EMISSIONS (CO2, CH4 , N2O, NO, NO2, NH3 )
WATER BALANCE (Evaporation, transpiration)
SOIL PROFILES (C and N contents, moisture etc.)
CROP PHENOLOGY (biomass etc)
=> for 28 crops
from Matthews et al. 2000
Conclusion
Mitigation:
Rice systems have to become more efficient in terms of…
• Water use • Fertilizer uptake • Harvest index
Challenges of Mitigation = Challenges of advanced resource management