title: Elevated CO2 facilitates C and N accumulation in a rice paddy ecosystem.
abstract: Elevated CO2 can stimulate wetland carbon (C) and nitrogen (N) exports through gaseous and dissolved pathways, however, the consequent influences on the C and N pools are still not fully known. Therefore, we set up a free-air CO2 enrichment experiment in a paddy field in Eastern China. After five year fumigation, we studied C and N in the plant-water-soil system. The results showed: (1) elevated CO2 stimulated rice aboveground biomass and N accumulations by 19.1% and 12.5%, respectively. (2) Elevated CO2 significantly increased paddy soil TOC and TN contents by 12.5% and 15.5%, respectively in the 0-15 cm layer, and 22.7% and 26.0% in the 15-30 cm soil layer. (3) Averaged across the rice growing period, elevated CO2 greatly increased TOC and TN contents in the surface water by 7.6% and 11.4%, respectively. (4) The TOC/TN ratio and natural δ15N value in the surface soil showed a decreasing trend under elevated CO2. The above results indicate that elevated CO2 can benefit C and N accumulation in paddy fields. Given the similarity between the paddies and natural wetlands, our results also suggest a great potential for long-term C and N accumulation in natural wetlands under future climate patterns.
authors.affiliation: Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China.; Institute of Applied Ecology, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: gjiaty@163.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Institute of Applied Ecology, Nanjing Agricultural University, Nanjing 210095, China; Technology Center of China Tobacco Fujian Industrial Co., Ltd., Xiamen 361021, China.
authors.forename: Mingqian
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China.; Chinese Academy of Engineering, Beijing 100088, China. Electronic address: wxw@cae.cn.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Applied Ecology, Nanjing Agricultural University, Nanjing 210095, China; Institute of Crop Science, Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Ecology, Physiology & Production, Ministry of Agriculture, Beijing 100081, China. Electronic address: zhangweij@caas.net.cn.
authors.forename: Weijian
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000383:Agriculture / Q000379:methods*; D018533:Biomass; D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry* / Q000378:metabolism; D017753:Ecosystem; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism; D012275:Oryza / Q000502:physiology*; D012987:Soil / Q000737:chemistry
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen
keywords: Carbon (C); Free-air CO(2) enrichment (FACE); Nitrogen (N); Paddy field; Wetland ecosystem