title: Effects of tillage and nitrogen fertilizers on CH4 and CO2 emissions and soil organic carbon in paddy fields of central China.
abstract: Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha(-1)) on fluxes of CH(4) and CO(2), and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH(4) emissions by 13%-66% and SOC by 21%-94% irrespective of soil sampling depths, but had no effect on CO(2) emissions in either year. Tillage significantly affected CH(4) and CO(2) emissions, where NT significantly decreased CH(4) emissions by 10%-36% but increased CO(2) emissions by 22%-40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%-48% in the 0-5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0-20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered.
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Li
authors.initials: L
authors.lastname: Cheng-Fang
authors.forename: Zhou
authors.initials: Z
authors.lastname: Dan-Na
authors.forename: Kou
authors.initials: K
authors.lastname: Zhi-Kui
authors.forename: Zhang
authors.initials: Z
authors.lastname: Zhi-Sheng
authors.forename: Wang
authors.initials: W
authors.lastname: Jin-Ping
authors.forename: Cai
authors.initials: C
authors.lastname: Ming-Li
authors.forename: Cao
authors.initials: C
authors.lastname: Cou-Gui
mesh_terms: D000383:Agriculture / Q000379:methods*; D002245:Carbon Dioxide / Q000737:chemistry*; D002681:China; D005308:Fertilizers; D008697:Methane / Q000737:chemistry*; D009584:Nitrogen / Q000494:pharmacology*; D009930:Organic Chemicals / Q000032:analysis*; D012275:Oryza / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development*; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D005308:Fertilizers; D009930:Organic Chemicals; D012987:Soil; D002245:Carbon Dioxide; D009584:Nitrogen; D008697:Methane