[Flux Characteristics of CO2, CH4, and N2 O and their Influencing Factors in Different Types of Ditches on the Chengdu Plain].

ABSTRACT

In order to study the flux characteristics of CH4, CO2 and N2O 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 that① Affected by human activities, CO2, CH4, and N2O 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. ② The 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 N2O 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 N2O fluxes, and DO (dissolved oxygen) and TN (total nitrogen) were the main environmental factors affecting CO2 and N2O fluxes. NH4+-N (ammonium nitrogen) and DO were the main water quality parameters affecting the CH4 flux.