Greenhouse gas emission from direct seeding paddy field under different rice tillage systems in central China

摘要

Agricultural tillage practices play an important role in the production and/or consumption of green house gas (GHG) that contributes substantially to the observed global warming. Central China is one of the world's major rice producing areas but a few studies have tried to characterize the mechanisms of GHG release from rice paddy field and quantify global warming (GWPs) based on GHGs emission on this region. In this study four tillage systems consisting of no-tillage with no fertilizer (NT0), conventional tillage with no fertilizer (CT0), no-tillage with compound fertilizer (NTC) and conventional tillage with compound fertilizer (CTC) applications in rice (Oryza sativa L.) cultivation were compared in terms of the carbon dioxide (CO), methane (CH) and nitrous oxide (NO) emissions from different tillage systems of the subtropical region of China during the rice growing season in 2008. GWPs based on CO, CH and NO's cumulative emissions were also compared. Tillage and fertilization had no influence on CO emissions. No-tillage had no effect on NO emissions but significantly affected CH emissions. Application of fertilizer significantly affected CH and NO emissions. Higher CH emissions and lower NO emissions were observed in CTC than in NTC. Cumulative CH emission flux in NTC was 51.68gCH mpo while it was 65.96gCH mpo in CTC, 28% (p <0.05) higher than that in NTC. Cumulative NO emission flux in CTC was 561.00mgNOmpo, and was 741.71mgNOmpo in NTC, 33% (p <0.05) higher than that in CTC. There was no significant difference in NO emissions between NT0 and CT0 systems, but significant in CH emissions. GWP of CTC was 26011.58kgCO hap#, which was 12% higher than that in NTC (23361.3kgCO hap#), therefore our findings show that no-tillage system was an effective strategy to reduce GWP from rice paddies in central China and thus can serve as a good agricultural system for environmental conservation.