It should be noted that while the
2.2. Gas sampling and flux measurement
The soil–atmosphere flux (F, mol m− 2 h− 1) of each greenhouse gas was finalized by following the formula:equation(1)F=VΔM/AρF=VΔM/Aρwhere V (m3) is the air volume left within the closed chamber after the open end of the chamber was inserted into the sediment; ΔM (h− 1) is the difference in gas concentration within the chamber; A (m2) is the surface area of FG2216 covered by the chamber and ρ (m3 mol− 1) is the volume of gas per mol under the atmospheric pressure then.
CO2-equivalent greenhouse gas fluxes (Fe, mg CO2 m− 2 h− 1) of N2O and CH4 were determined following the formula:equation(2)Fe=F×M×GMPFe=F×M×GMPwhere F is thorax the flux of greenhouse gas, M is the molecular weight of the greenhouse gas and GMP represents the global warming potential of the greenhouse gas when compared to CO2 over a 100 year time scale, which is 296 for N2O ( IPCC, 2007) and 23 for CH4 ( Shindell et al., 2009), respectively.