Methane and nitrous oxide emissions from direct-seeded and seedling-transplanted rice paddies in southeast China

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• 作者：Shuwei Liu (1)
  Yaojun Zhang (1)
  Feng Lin (1)
  Ling Zhang (1)
  Jianwen Zou (1)
  
• 关键词：CH4 ; Fertilizer application ; GWP ; GHGI ; N2O ; Rice cropping regime
• 刊名：Plant and Soil
• 出版年：2014
• 出版时间：January 2014
• 年：2014
• 卷：374
• 期：1-2
• 页码：285-297
• 全文大小：
• 作者单位：Shuwei Liu (1)
  Yaojun Zhang (1)
  Feng Lin (1)
  Ling Zhang (1)
  Jianwen Zou (1)
  
  1. Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing Agricultural University, Nanjing, 210095, China
  
• ISSN：1573-5036

文摘

Background and aims The rice production is experiencing a shift from conventionally seedling-transplanted (TPR) to direct-seeded (DSR) cropping systems in Southeast Asia. Besides the difference in rice crop establishment, water regime is typically characterized as water-saving moist irrigation for DSR and flooding-midseason drainage-reflooding and moist irrigation for TPR fields, respectively. A field experiment was conducted to quantify methane (CH4) and nitrous oxide (N2O) emissions from the DSR and TPR rice paddies in southeast China. Methods Seasonal measurements of CH4 and N2O fluxes from the DSR and TPR plots were simultaneously taken by static chamber-GC technique. Results Seasonal fluxes of CH4 averaged 1.58?mg?m?2?h?1 and 1.02?mg?m?2?h?1 across treatments in TPR and DSR rice paddies, respectively. Compared with TPR cropping systems, seasonal N2O emissions from DSR cropping systems were increased by 49?% and 46?% for the plots with or without N application, respectively. The emission factors of N2O were estimated to be 0.45?% and 0.69?% of N application, with a background emission of 0.65 and 0.95?kg N2O-N?ha?1 under the TPR and DSR cropping regimes, respectively. Rice biomass and grain yield were significantly greater in the DSR than in the TPR cropping systems. The net global warming potential (GWP) of CH4 and N2O emissions were comparable between the two cropping systems, while the greenhouse gas intensity (GHGI) was significantly lower in the DSR than in the TPR cropping systems. Conclusions Higher grain yield, comparable GWP, and lower GHGI suggest that the DSR instead of conventional TPR rice cropping regime would weaken the radiative forcing of rice production in terms of per unit of rice grain yield in China, and DSR rice cropping regime could be a promising rice development alternative in mainland China.