For example, when measuring both CH4 and N2O fluxes to estimate seasonal cumulative
emissions, measurements should start before the first agricultural management event of the
rice growing season (e.g., tillage, basal fertilization, or organic amendment), before actual rice
cultivation begins, and should continue until harvest. We sometimes see seasonal CH4 flux
data in which the initial flux value is already high (i.e., not near zero). Such data are difficult to
interpret because the actual start (and end) of the rice growing season cannot be determined.
Similarly, a substantial N2O flux after harvest may be caused by, for example, the
incorporation of rice straw into the soil. The definition of the rice growing season depends on
local practices, the annual number of rice crops, etc