Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2
flux measurements, particularly in natural and semi-natural terrestrial ecosystems. The 15
N gas-flux method was adapted by lowering the 15
N tracer application rate to 0.04–0.5 kg 15
. The minimum detectable flux rates were 4 μg N m−2
and 0.2 ng N m−2
for the N2
O fluxes respectively. The acetylene inhibition technique underestimated denitrification rates by a factor of 4.