成都平原不同类型沟渠CO_2、CH_4和N_2O排放通量特征及其影响因素

Flux Characteristics of CO_2,CH_4,and N_2O and their Influencing Factors in Different Types of Ditches on the Chengdu Plain

为研究不同类型沟渠CH_4、CO_2和N_2O排放通量特征及其影响因素,于2014年3月~2015年2月,以每月一次的频率,采用静态浮箱法对成都平原的农业沟渠、农业生活复合沟渠、生活沟渠的CH_4、CO_2和N_2O排放通量进行监测.结果表明:(1)受人为活动的影响,研究区域中3种类型的沟渠CO_2、CH_4和N_2O排放通量较大,变化范围分别为-2.26~1 504.40mg·(m^2·h)^(-1)、0.69~40.00 mg·(m^2·h)^(-1)、-2.27~70.35μg·(m^2·h)^(-1),且均表现出夏季高,冬季低的特征.(2)农业生活复合沟渠CO_2排放通量显著高于农业沟渠和生活沟渠(P<0.05),生活沟渠CH_4和N_2O排放通量显著高于农业生活复合沟渠和农业沟渠(P<0.05).(3)水温和降雨量是影响CO_2、CH_4和N_2O排放通量的主要环境因子,溶解氧(dissolved oxgen,DO)和全氮(total nitrogen,TN)是影响CO_2和N_2O排放通量的主要水质参数;铵态氮(ammonium nitrogen,NH_4^+-N)与DO是影响CH_4排放通量的主要水质参数.

In order to study the flux characteristics of CH4 , CO2 and N2 O in different ditches and their influencing factors, three types of ditches （an agricultural ditch, agricultural-living compound ditch, and living ditch） were monitored once a month from March 2014 to February 2015 using static floating chambers in the Chengdu Plain. The results showed that： ①Affected by human activities, CO2 , CH4 , and N2 O fluxes were high in ditches and ranged from - 2. 26- 1504. 40 mg·（m2·h） - 1 , 0. 69- 40. 00 mg·（m2·h） - 1 , and- 2. 27-70. 35 μg·（m2·h） - 1 ,respectively. All are higher in summer compared to autumn and spring, and are lowest in winter. ②The flux of CO2 in agricultural-living compound ditches was significantly higher than that in agricultural ditches and living ditches （ P 〈0. 05）, and the fluxes of CH4 and N2 O in living ditches were significantly higher than those in agricultural ditches and agricultural-living compound ditches （P 〈 0. 05）. ③ Water temperature and rainfall were the main environmental factors affecting CO2 , CH4, and N2 O fluxes, and DO （dissolved oxygen） and TN （total nitrogen） were the main environmental factors affecting CO2 and N2 O fluxes. NH ＋4 -N （ammonium nitrogen） and DO were the main water quality parameters affecting the CH4 flux.