Nitrogen losses from agricultural soils through denitrification ‐ a critical evaluation

The direct measurement of gaseous N losses through denitrification requires a complicated methodology. Mostly alternative approaches are used to estimate these losses for a particular arable or grassland site. Evaluation of the literature shows that N losses as a result of denitrification ‐ determined by the 15 N balance, by direct mass spectrometry of N 2 + N 2 O and by the acetylene inhibition method, respectively ‐ may reach about 10 % of the fertilizer input on agriculturally used sites without irrigation or organic manure addition. The estimation of denitrification losses can be improved by considering site‐specific parameters affecting denitrification like total carbon content, pH, time of fertilizer application as well as soil temperature and soil moisture conditions.