Third, a thorough inventory cannot compensate for a lack of
local references with regards to direct field emissions. In rice
cropping, direct field emissions form the bulk of environmental
impacts. Although ideal, field measurements (tier-3 data) are
hardly feasible in conjunction with a research project such as the
one performed here. However, the exclusive use of generic baseline
emissions and factors (tier-1 data, such as the ones provided by
IPCC) may lead to massive errors. This research tried to adapt IPCC
standards and use some tier-2 information (regional data, compiled
by Yan et al., 2003a, 2003b); it also attempted to more accurately
model emissions to water.