2.4 Soil respiration measurement
The subset of air-dried soil samples was then pre-incubated for 14 days
at 25°C under flooded conditions. For each measurement of respiration
rate, approximately 20 g (equivalent dry weight) of each soil sample was
incubated in a 500-mL container at 25°C for 24 h. At the end of this
period, CO2 concentrations in the headspace were
measured using an Agilent-7890a gas chromatograph equipped with a flame
ionization detector (Agilent Technologies, Inc.). Soil respiration rates
were calculated from the net accumulation of CO2 over
time. The soil metabolic quotient (qCO2) was calculated
by dividing the soil respiration rate by the MBC content (Plaza et al.,
2004).