Reiner Wassman (IRRI): Modifying water management for rice production (presentation from Mitigation session at CCAFS Science Workshop, December 2010)

1. Modifying water management
for rice production

2. BUT
Rice
is
not
just
a
vic1m
of
climate
change,
it
is
also
one
of
the
causes

3. How
methane
is
produced
by
irrigated
rice
=> Rice fields account for 5 -20 % of all global
methane sources

4. ‘Closed Chamber‘ Method

5. Diurnal patterns
Pooled field data, Buendia et al. 1997

6. Relevance for CCAFS?
One of the Fund Council comments:
o Articulate potential contribution to
development of global standards for
measuring GHG emissions from
agriculture

7. Unit plot size: 5 x 5 m

8. Field stations of the Intenational Rice Research
Institute (projects funded by US-EPA and UNDP/ GEF)
IRRI/
Los Banos
Irrigated
Rainfed
Deepwater

9. View of the
field
chambers
(for flooded/
non-flooded
condition)

10. Mid-season drainage
Days after planting
Field experiment at Hangzhou, China (Wassmann et al., 2000)

12. ‘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

15. " downward flux – atmospheric CO2 taken up by
the rice plant for photosynthesis
" upward flux – CO2 being released from
ecosystem respiration

16. Modelling emissions using DNDC model
(DeNitrification-DeComposition)
Inputs
SOIL
Texture, pH, => for 28 crops
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)
from Li et al.
2000 SOIL PROFILES (C and N contents, moisture etc.)
CROP PHENOLOGY (biomass etc)

17. from
Matthews
et al. 2000

18. 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