• 关键词：稻田  大气CO₂浓度增高  可溶性有机碳  可溶性氮  全球变化

• 基金项目：教育部博士点基金;新世纪优秀人才资助计划(No.NCET-05-0492);科技部“十一五”支撑计划(No.2006BAD15B02,2006BAD02A15)

• 杨菲
• 南京农业大学应用生态研究所, 南京 210095

• 郭嘉
• 南京农业大学应用生态研究所, 南京 210095

• 户其亮
• 南京农业大学应用生态研究所, 南京 210095

• 朱建国
• 中国科学院南京土壤研究所, 南京 210008

• 张卫建
• 1. 南京农业大学应用生态研究所, 南京 210095; 2. 中国农业科学院作物科学研究所, 北京 100081

• 摘要：为了增强对全球变化背景下湿地生态系统碳氮循环的整体认识,采用稻田FACE(Free Air CO₂ Enrichment)试验(位于江苏省江都市,始于2004年)方法,研究了2006年位于江都市的稻田水体中总有机碳、总氮、可溶性有机碳、可溶性氮的动态变化.结果表明:大气CO₂浓度升高显著提高了稻田水体中以上各指标含量(p<0.01),其中各有机碳的增幅均大于相应的氮.与对照相比,FACE田块水体中总有机碳、总氮、可溶性有机碳和可溶性氮分别平均提高了31.2%、25.9%、28.3%和25.6%.不同生育时期各指标含量存在显著差异(p<0.01).上述结果还表明,大气CO₂浓度增高不仅会通过富营养化稻田水体来影响水稻安全生产,而且还会提高其中可溶性碳氮含量,进而可能通过田间排水尤其是水稻生长前期暴雨导致的洪涝来增加稻田碳氮向周边水域的输送,从而影响到稻田生态系统的碳氮循环和土壤生产力.

• Abstract：In order to enhance our understanding of carbon and nitrogen cycle in wetland ecosystems,total organic carbon(TOC),total nitrogen(TN),dissolved organic carbon(DOC) and dissolved nitrogen(DN) in paddy field water were monitored dynamically by Free Air CO₂ Enrichment(FACE) of the paddy field(started in 2004,located in Jiangdu County,Jiangsu province).The results showed that elevated atmospheric CO₂ significantly increased TOC,TN,DOC and DN by an average of 31.2%,25.9%,28.3% and 25.6%,respectively,over those in ambient air plots(p<0.01).There were significant differences in TOC,TN,DOC and DN between different rice growing stages(p<0.01).The results also indicated that elevated atmospheric CO₂ could threat rice security production through eutrophicating paddy field water and increasing aquatic DOC and DN.Therefore elevated atmospheric CO₂ may influence the rice ecosystem C and N cycle and soil productivity through field drainage and rainstorms in the early stages of rice growth.

• Key words：paddy field  elevated atmospheric CO₂  dissolved organic carbon  dissolved nitrogen  global change

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