2015 Asia Sub-Group Meeting of GRA-PRRG, Sep. 19, 2015, Nanjing, China On-going research activities to mitigate GHGs emission from rice paddy in China Xiaoyuan Yan (Institute of Soil Science, Chinese Academy of Sciences)
Rice production in China Production (million ton) 100 150 200 250 50 0 1980 1981 1982 Production of grains 1983 1984 1985 1986 1987 1988 Rice 1989 1990 1991 1992 1993 1994 1995 Wheat 1996 1997 1998 1999 2000 2001 2002 2003 2004 Maize 2005 2006 2007 2008 2009 2010 2011 2012 2013 Cultivation area (million ha) 10 15 20 25 30 35 40 0 5 1980 1981 1982 1983 1984 Sown area of rice 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Spatial distribution rice production
Share of agriculture in total GHG Second national communication: 2005 Rice paddy: ~2.5% of total emission
On-going national projects MOA project MOST project • • Development of Agricultural GHG Development, integration and monitoring and controlling demonstration of technology technologies of carbon • Monitoring technology, standard sequestration and GHG and quality control mitigation for croplands • Options for livestock industry • • Options for grazing pasture Core mitigation technology • Options for uplands in northeast and scaling method • China Mitigation options for rice • Options for uplands in northwest paddy • China Mitigation options for • Options for uplands in north China upland Plain • Options for single-rice paddy • Options for double-rice paddy
Mitigation options 1. Residue management 2. Water-saving cultivation 3. Water-saving rice variety 4. Rice-duck cultivation 5. Multiple technology integration
Effect of straw application 28 26 -1 ) 24 2 -eq ha 22 20 y=x 18 16 Straw-induced GWP (t CO Yixing, this study 14 Taoyuan, this study 12 Changshu, China 10 Yixing, China Kalasin, Thailand 8 Hokkaido, Japan y=x 6 Jiangning, China 4 2 0 0 2 4 6 8 10 12 14 16 18 20 -1 ) Straw carbon input (t CO 2 -eq ha 0 1 2 3 4 5 6 7 -1 ) Soil carbon sequestration (t CO 2 -eq ha
Effect of crop residue on rice yield Singh et al., 2008, Advances in Agronomy
1. Residue management Biochar application
Effect of biochar on CH 4 emission straw biochar control Feng YZ et al., 2012, SBB.
2. Plastic film mulching cultivation Non-flooded plastic film mulching cultivation
传统栽培 覆膜栽培 Plastic Mulch Traditional Significant drought resistance effect 传统栽培 覆膜栽培 Traditional Plastic Mulch
Reasons for yield benefit Contradiction between water and 排灌方便，节水保水 temperature Easy drainage and irrigation; saves water 厢沟保水，厢面增温 关水 → 低温 → 坐蔸 Water in ditch – No drought, higher temperature Flooding Low temp Slow growth in raised bed 放水 → 干旱 → 不长 Drained Drought Poor growth
Effect of plastic film mulch on soil temperature 50 Soil surface (0 cm depth) 45 40 土壤温度 Soil temperature(C 0 ) 35 30 25 20 9:00 10:00 11:00 14:00 16:00 18:00 10:00 11:00 12:00 14:00 16:00 18:00 15:00 18:00 9:00 12:00 12:00 50 9:00 45 Soil subsurface (10 cm depth) 40 晚期分蘖 Late tillering 早期分蘖 Early tillering 35 中期分蘖 Middle tillering 30 25 20 12:00 15:00 18:00 9:00 18:00 10:00 11:00 14:00 16:00 18:00 10:00 12:00 16:00 11:00 14:00 9:00 12:00 9:00 时间 Time of day (hour:minute) PM SM TF 传统淹水 地膜覆盖 稻草覆盖 Traditional Flooding Straw Mulch Plastic Mulch
Plastic Traditional Straw mulch flooding mulch
Rice yield with different mulching materials and N rate
四川 资 阳：栽培方式与 脲酶 / 硝化抑制 剂 施用。
CH 4 emissions TF TF-DCD/HQ PM PM-DCD/HQ 50 50 -2 ) Convent TF 40 4 m 40 NI+UI TF-DCD/HQ CH 4 emission (g CH -1 ) -2 h 30 Film PM 4 m 30 CH 4 flux (mg CH FM+NI+UI PM-DCD/HQ 20 20 10 Transplanting 0 10 Film Convent NI+UI FM+NI+UI 0 0 30 60 90 120 Days after flooding (Apr. 18, 2010)
N 2 O emissions TF TF-DCD/HQ PM PM-DCD/HQ 1500 600 Convent TF -2 ) 2 O-N m -1 ) 1200 500 NI+UI TF-DCD/HQ -2 h 2 O-N m Film PM 400 N 2 O emission (mg N 900 FM+NI+UI PM-DCD/HQ 300 N 2 O flux (μg N 600 Transplanting 200 100 300 0 Film Convent NI+UI FM+NI+UI 0 0 30 60 90 120 Days after flooding (Apr. 18, 2010) Compared to conventional, FM enhanced N 2 O emission by 3.77-fold. Application of DCD/HQ reduced N 2 O emission by 79-81%.
Integrated GWP
More durable plastic film is easier to remove and prevent the plastic pollution effectively!
Incentives Economic analysis, yuan/ha Conventiona Items Film mulching l Fertilizer input 1620 1188 Pesticide input 525 300 Film cost 0 750 Labor cost 6000 3300 Yield benefit 6750 9000 Net economic 630 6582 benefit
Climate-smart, environmentally friendly Economic analysis, yuan/ha Conventio Film Items • 4 Savings: irrigation, nal mulching fertilizer, pesticide, Fertilizer 1620 1188 input labor Pesticide • 2 Early: transplant, 525 300 input harvest Film cost 0 750 Labor cost 6000 3300 • 2 Increase: yield, Yield benefit 6750 9000 profit Net economic 630 6582 • 1 Decrease: GHG benefit
3. Drought-resistant rice variety • Full irrigation condition • Rice-yield:+0-8% • 50% water saving condition • Rice yield: +50% • GHG: ?
Drought-resistant rice variety • Rice varieties: • Drought-resistant (D/r) variety • Traditional variety • Irrigation amount : • Normal irrigation (100% irrigation, IR100%) • 70% of normal irrigation (70% irrigation, IR70%) • 30% of normal irrigation (30% irrigation, IR30%)
Yield depends on rainfall Rainfall and irrigation Rice yield Yield （ t/ha ） Y Rainfall in jun- Irrigation Actual water Treatme e Year Treatment sep （ mm ） （ mm ） use （ mm ） a nt Drought- Convention r resistant al 30% 灌 272 184 455 30% 灌 8.2 ± 0.4 7.9 ± 0.0 2 2013 70% 灌 272 428 700 0 70% 灌 8.6 ± 0.3 8.3 ± 0.2 1 3 100% 灌 272 612 884 100% 灌 8.7 ± 0.1 8.8 ± 0.1 30% 灌 9.3 ± 0.1 9.8 ± 0.1 30% 灌 763 35 798 2 0 70% 灌 9.3 ± 0.1 10.0 ± 0.2 2014 70% 灌 1 763 82 844 4 100% 灌 9.4 ± 0.1 10.1 ± 0.2 100% 灌 763 117 879
Yield-scaled emission 1000 旱优 8 号 花优 14 Drought- Conve resistant 800 ntional GHGI (kg-CO2eq/ton) 600 400 200 0 30% 灌 70% 灌 100% 灌 30% 灌 70% 灌 100% 灌 2013 2014
4. Rice-duck system A rising rice cultivation system in south China Incentives: • Improving economic income •Saving pesticide …
10 Rice-duck 9 CK 8 7 Rice yield (t/ha) 6 5 4 3 2 1 0 2013 late rice 2014 eary rice 2014 late rice
CH4 emission from rice-duck system 40 Year:2013 35 30 CH4 flux (mg/m2/h) 25 20 Rice-duck Conventional 15 10 5 0 7/25/13 8/14/13 9/3/13 9/23/13 10/13/13 11/2/13 Time Yield scaled Emission reduction Year Season Treatment Total CH4 (g/m2) emission(g/kg) (%) 17.2 Rice-duck 22.7 27.9 2013 Late rice CK 30.2 33.7 15.9 Rice-duck 27.37 35.93 Early rice CK 32.5 42.742 2014 35.8 Rice-duck 26.36 29.46 Late rice CK 31.91 45.91
Why CH 4 emission is reduced? a concentration(mg L -1 ) a Dissolved oxygen b a a a b b Date(day-month) Year:2013
5. Technology integration
Integration of technologies Aerobic residue Rotation change CO 2 utilization fermentation
CO2 CK
Seasonal CH4 emission Rice yield 400 10000 Rice-wheat Rice-bean Rice-wheat Rice-bean 9000 350 8000 CH4 emission (kg/ha) 300 Rice yield (kg/ha) 7000 250 6000 200 5000 4000 150 3000 100 2000 50 1000 0 0 0 120 180 240 0 120 180 240 N application rate (kgN/ha) N application rate (kgN/ha)
2.00 CH4 emission SOCSR Irrigation N fertilization Others 1.80 Rice-wheat 1.60 C footprint (kg CO2-eq/kg grain) 1.40 Rice-bean 1.20 1.00 0.80 0.60 0.40 0.20 0.00 RW0 RW120 RW180 RW240 RB0 RB120 RB180 RB240 -0.20
Other technologies Ridged cultivation Low emission cultivar Inhibitors
SUMMARY • GHG emission from rice cultivation accounts for about 2.5% of nation total. • Promising mitigation practice includes plastic film mulching, biochar application, crop rotation change • Many of the mitigation options have environmental and economic synergies.
Thank you and my collaborators: Hua Xu (Institute of Soil Science, CAS) Xiangfu Song (Shanghai Academy of Agricultural Sciences) Zhiqiang Fu (Hunan Agricultural University)
Factors affecting CH 4 emission Equation 5.1 CH 4 Emissions from Rice Cultivation Emissions from Rice Cultivation (Gg/yr) = ijk (EF ijk t ijk A ijk 10 -6 ) i, j, and k: different ecosystems, water regimes, organic amendments, etc. Equation 5.2 Adjusted Daily Integrated Emission Factor EFi = EFc SFw SFp SFo SFs,r
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