大气CO_2浓度和温度升高对稻麦轮作生态系统N_2O排放的影响  

Response of N_2O Emissions to Elevated Atmospheric CO_2 Concentration and Temperature in Rice-Wheat Rotation Agroecosystem

作　　者：王从 李舒清 刘树伟 邹建文 WANG Cong;LI ShuQing;LIU ShuWei;ZOU JianWen(College of Resources and Environmental Sciences,Nanjing Agricultural University/Jiangsu Province Key Laboratory for Organic Solid Waste Utilization,Nanjing 210095)

机构地区：[1]南京农业大学资源与环境科学学院/江苏省固体有机废弃物资源化高技术研究重点实验室,南京210095

出　　处：《中国农业科学》2018年第13期2535-2550,共16页Scientia Agricultura Sinica

基　　金：国家杰出青年科学基金(41225003);江苏省高校优势学科建设工程资助项目(PAPD)

摘　　要：【目的】研究大气CO_2浓度和温度升高条件下稻麦轮作生态系统N_2O排放的响应规律,以期科学评估未来气候变化情境下,CO_2浓度和温度升高对稻麦轮作生态系统N_2O排放的影响,为中国应对未来气候变化提供数据支持。【方法】依托同步模拟自由大气CO_2浓度升高和温度升高的T-FACE试验平台,设置本底大气CO_2浓度和温度(Ambient)、500μmol·mol^(-1) CO_2+本底大气温度(C)、本底大气CO_2浓度+温度增加2℃(T)和500μmol·mol-1 CO_2+温度增加2℃(C+T)等4个处理。采用静态暗箱-气相色谱法原位观测稻麦轮作生态系统N_2O排放通量,研究稻麦轮作生态系统N_2O排放对大气CO_2浓度和温度升高的响应规律。【结果】(1)CO_2浓度升高使水稻和小麦生物量和产量分别显著增加9.7%、11.3%和5.6%、5.7%(P<0.05);温度升高使水稻和小麦生物量和产量分别显著减少21.1%、18.0%和31.6%、17.7%(P<0.05);CO_2浓度和温度的同步升高使水稻和小麦生物量和产量分别显著降低13.5%、8.7%和26.0%、10.3%(P<0.05)。(2)CO_2浓度和温度升高,均未改变稻麦轮作系统N_2O的季节排放模式。CO_2浓度升高条件下,水稻季和小麦季N_2O排放分别增加15.2%和39.9%,其中后者达显著水平(P<0.05);温度升高未显著影响水稻季N_2O排放,但显著增加小麦季N_2O排放20.5%(P<0.05);CO_2浓度和温度同步升高对水稻季N_2O排放的影响存在较大的年际差异,但总体上有促进N_2O排放的趋势;CO_2浓度和温度同步升高极显著增加小麦季N_2O排放(46.0%,P<0.01)。(3)小麦季N_2O排放与小麦生物量密切相关,在CO_2浓度和温度升高条件下,小麦季N_2O排放与小麦地下部生物量和ΔSOC之间具有显著的正相关关系。(4)与对照组相比,CO_2浓度升高、温度升高以及两者的共同作用,分别导致稻麦轮作系统单位产量的N_2O排放强度(GHGI)分别增加29.1%、66.3%和81.8%,其中温度升高和CO_2浓度和温度同步升高处理达�【Objective】This study was conducted to examine the effects of elevated atmospheric carbon dioxide（CO2） concentration and temperature on nitrous oxide（N2O） emissions from annual rice-wheat rotation systems, so as to gain an insightinto N2O fluxes response to climate change.【Method】An in-situ field experiment was established in annual rice-winter wheat rotation systems under a T-FACE platform, consisting of four treatments under different CO2 concentration and temperature levels（ambient CO2 ＋ ambient temperature, ambient; 500 μmol·mol^-1 CO2 ＋ ambient temperature, C; ambient CO2 ＋ temperature increased by 2℃, T; 500 μmol·mol^-1 CO2 ＋ temperature increased by 2℃, C＋T） during 2012-2015. The fluxes of N2O from rice-wheat rotation fields were measured using static opaque chamber-gas chromatograph method.【Result】（1） On an average of two rice-growing seasons, elevated atmospheric CO2 concentration significantly increased the biomass and yield of rice by 9.7% and 5.6%, respectively, and those increments of wheat were 11.3% and 5.7% over the three wheat-growing seasons（P〈0.05）, respectively; Elevated temperature significantly reduced the biomass and yield of rice by 21.1% and 31.6%, and those reductions of wheat were 18.0% and 17.7%, respectively; The combination of elevated CO2 and temperature significantly reduced the biomass and yield of rice by 13.5%（P〈0.05）and 26.0%, and those reductions of wheat were 8.7% and 10.3%（P〈0.05）, respectively.（2） Either elevated CO2 concentration or temperature did not affect the seasonal patterns of N2O emission from rice-wheat rotation system. Elevated CO2 concentration increased N2O emissions in rice and wheat season by 15.2% and 39.9%, respectively. Elevated temperature did not affect N2O emissions in rice season, but it significantly increased N2O emissions in wheat season by 20.5%（P〈0.05）. Despite of a considerable interannual variability, N2O emissions tended to be increased by the combined effect of elevated

关 键 词：T-FACE 稻麦轮作 CO2 温度 生物量 产量 N2O 温室气体排放强度 

分 类 号：S511[农业科学—作物学] S512.1