N 2 O is a major greenhouse gas and the majority of anthropogenic N 2 O emissions originate from agriculturally managed soils. Therefore, developing N 2 O mitigation strategies is a key challenge for the agricultural sector and biochar soil treatment is one reported option. Biochar's capacity to increase soil pH and to foster activity of specialized N 2 O reducers has been proposed as possible mechanisms for N 2 O mitigation. An experiment was undertaken to investigate whether changes in the community composition of N 2 O reducers was observed under field conditions after biochar application. The study objective was to assess the abundance and taxonomic composition of the functional marker genes nosZ and nosZ –II across a vegetation period of Zea mays L. after biochar or lime addition compared to an untreated control. After fertilization, biochar amendment resulted in a significant increase of nosZ gene copy numbers compared to the control and the lime treatment. Simultaneously a shift in community composition of nosZ-II bearing bacteria was observed in the biochar treatment that went beyond the sole liming effect. This study broadens our understanding of the functional impact of biochar on N 2 O emissions and emphasizes the possibility to shape the functioning of the N 2 O reducing microbial community through the addition of biochar at a field scale.