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Greenhouse Gas Mitigation Options from Rice Field. Sirintornthep Towprayoon The Joint Graduate School of Energy and Environment King Mongkut’s University of Technology Thonburi Bangmod, Bangkok, Thailand 10140.
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Greenhouse Gas Mitigation Options from Rice Field Sirintornthep Towprayoon The Joint Graduate School of Energy and Environment King Mongkut’s University of Technology Thonburi Bangmod, Bangkok, Thailand 10140 Presented at In-session workshop on Climate Change Mitigation 19 Bonn 2004, Maritim Hotel,Bonn
Background • Rice fields contribute approximately 9-13 percent of the global greenhouse gases • Methane and nitrous oxide are the dominant GHG emission
Mechanism • To implement mitigation options need well understanding of the emission mechanisms • Interaction between rice plant, microbe, the environmental condition in the soil, and the cultural condition of the farmer • Methane produced by methanogen under anaerobic condition in the rice field • Nitrous oxide produced by nitrifying and denitrifying bacteria under the anoxic condition • Rice plant, during reproductive growth excrete some essential nutrient and activated microbial growth
fertilizer Growth and development Height, mass,density Rice varieties Emission Production soil properties Root exudates Indigenous Microorganisms
water regimes Height, mass,density Rice varieties Emission Production Anaerobic and anoxic condition Indigenous Microorganisms
Mitigation options • Factor affecting GHG emission • Land preparation • Seed preparation • Rice varieties • Fertilizer application • Water management • Harvesting and fallow period
Land preparation Dry land level Wet land level
Seed preparation Direct seeding Pre-germinated seed and seedlings Transplanting or Casting
The choice of mitigation options • Ultimate goal : High yield and GHGs reduction • Economic aspect • Low cost : investment, labor, machinery • Market : positive expandable market, good price • Governmental subsidy • Social aspect • Acceptable by farmers • Easy to implement • Undisturbed farmer way of life
Options chosen • Water management • Reduce GHG • Economic : not involved with investment • Easy to implement and being accepted by farmer • Shifting fertilizer application • Reduce GHG • Economic : less invesment
Options of water management • In common practice, water was drained out of the field during vegetative period. • Drainage reduce methane but promote nitrous oxide • Shifting drainage time from vegetative period to reproductive period help reduce methane production and emission • Shorten drainage day also help reduce nitrous oxide emission
Methane emission and soil redox potential from 4 different drainage rice fields
Nitrous oxide and methane emission from 4 different drainage rice fields
Yield and GHG Emission • Area of irrigated rice field (local practice) is 3 times greater than area of rain fed rice field ( continuous flooding) • Three scenarios have been set up • Continuous flooding and local practice (base case) • Continuous flooding and midseason drainage • Continuous flooding and multiple drainage • All midseason drainage
Option of fertilizer application • Two time of fertilizer application : basal fertilizer and top dressing fertilizer • In general, urea is use as the common fertilizer • Ammonium sulphate (inhibit methanogen) and ammonium phosphate ( promote rice plant growth ) was applied in substitute to urea
Conclusion(1) • GHG emission from rice field is ‘survival emission’ • The implementation need to be carefully considered • The options should not impact on the farmer’s way of life as well as theirs investment but should promote theirs income
Conclusion(2) • Aprox. 25 percent of GHG reduction could achieve in comparison to base case • Options to reduce GHGs impact on rice yield • Optimizing between GHG reduction and yield need to be concerned
Acknowledgement • Thailand research fund • Ms. Saipin Poonkaew and Ms. Kruamas Smaghan
