Methane and nitrous oxide emissions from organic and conventional rice cropping systems in Southeast China
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To evaluate the impacts of organic cropping system on global warming potentials (GWPs), field measurements of CH4 and N2O were taken in conventional and organic rice (Oryza sativa L.) cropping systems in southeast China. Rice paddies were under various water regimes, including continuous flooding (F), flooding–midseason drainage–reflooding (F-D-F), and flooding–midseason drainage–reflooding and moisture but without waterlogging (F-D-F-M). Nitrogen was applied at the rate of 100 kg N ha−1, as urea-N or pelletized, dehydrated manure product in conventional or organic rice paddies, respectively. Seasonal fluxes of CH4 averaged 4.44, 2.14, and 1.75 mg m−2 h−1 for the organic paddy plots under the water regimes of F, F-D-F and F-D-F-M, respectively. Relative to conventional rice paddies, organic cropping systems increased seasonal CH4 emissions by 20%, 23%, and 35% for the plots under the water regimes of F, F-D-F, and F-D-F-M, respectively. Under the water regimes of F-D-F and F-D-F-M, seasonal N2O-N emissions averaged 10.85 and 13.66 μg m−2 h−1 in organic rice paddies, respectively, which were significantly lower than those in conventional rice paddies. The net global warming potentials (GWPs) of CH4 and N2O emissions from organic rice paddies relative to conventional rice paddies were significantly higher or comparable under various water regimes. The greenhouse gas intensities were greater, while carbon efficiency ratios were lower in organic relative to conventional rice paddies. The results of this study suggest that organic cropping system might not be an effective option for mitigating the combined climatic impacts from CH4 and N2O in paddy rice production.
KeywordsCH4 Global warming potential (GWP) Mitigation for greenhouse gases N2O Organic agriculture Rice paddy
This work was supported by the Special Fund for Basic Scientific Research of Central Colleges, NAU (Y201018), the NSFC (40971140), the FANEDD (200969), and the NCET (08-0798).
- FAO (2002) Organic agriculture, environment and food security. FAO, RomeGoogle Scholar
- FAO (2003) World agricultural towards 2015/2030. An FAO Perspective. FAO, RomeGoogle Scholar
- Forster P, Ramaswamy V, Artaxo P, Berntsen T, Betts R, Fahey DW, Haywood J, Lean J, Lowe DC, Myhre G, Nganga J, Prinn R, Raga G, Schulz M, Van Dorland R (2007) Changes in atmospheric constituents and in radiative forcing. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Climate change 2007: the physical science basis. Contribution of working group i to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 130–234Google Scholar
- Li C, Frolking S, Xiao X, Moore B III, Boles S, Qiu J, Huang Y, Salas W, Sass R (2005) Modeling impacts of farming management alternatives on CO2, CH4 and N2O emissions: a case study for water management of rice agriculture of China. Global Biogeochem Cycles 19:3010Google Scholar
- Lu D, Zong L, Xiao X, Yang Y, Zhou Z, Xi Y (2005) A comparison of heavy metals concentration in soils of organic and conventional farming in typical regions of eastern China. J Agro-Environ Sci 24:143–147 (in Chinese with English abstract)Google Scholar
- Neue H-U, Sass RL (1998) The budget of methane from rice fields. IGACtivities Newsletter 12:3–11Google Scholar
- Smith CJ, Brandon M, Partrick WH Jr (1982) Nitrous oxide emission following urea-N fertilization of wetland rice. Soil Soc Plant Nutr 28:161–171Google Scholar
- Smith P, Martino D, Cai Z, Gwary D, Janzen H, Kumar P, McCarl B, Ogle S, O’Mara F, Rice C, Scholes B, Sirotenko O (2007) Agriculture. In: Metz B, Davidson OR, Bosch PR, Dave R, Meyer LA (eds) Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, pp 497–540Google Scholar
- Smith P, Martino D, Cai Z, Gwary D, Janzen H, Kumar P, McCarl B, Ogle S, O’Mara F, Rice C, Scholes B, Sirotenko O, Howden M, McAllister T, Pan G, Romanenkov V, Dchneider U, Towprayoon S, Wattenbach M, Smith J (2008) Greenhouse gas mitigation in agriculture. Phil Trans R Soc B 363:789–813CrossRefPubMedGoogle Scholar
- USEPA (2006) Global anthropogenic non-CO2 greenhouse gas emissions: 1990–2002. Office of Atmospheric Programs, USEPA, Washington, DC Available at: http://www.epa.gov/nonco2/econ-inv/pdfs/global_emissions.pdf.