The introduction of legumes into crop sequences and the reduction of tillage intensity are both proposed as agronomic practices to mitigate the soil degradation and negative impact of agriculture on the environment. However, the joint effects of these practices on nitrous oxide (N2O) and ammonia (NH3) emissions from soil remain unclear, particularly concerning semiarid Mediterranean areas. In the frame of a long-term field experiment (23 years), a 2-year study was performed on the faba bean (Vicia faba L.) to evaluate the effects of the longterm use of no tillage (NT) compared to conventional tillage (CT) on yield and N2O and NH3 emissions from a Vertisol in a semiarid Mediterranean environment. Changes induced by the tillage system in soil bulk density, water filled pore space (WFPS), organic carbon (TOC) and total nitrogen (TN), denitrifying enzyme activity (DEA), and bacterial gene (16S, amoA, and nosZ) abundance weremeasured as parameters potentially affecting N gas emissions. No tillage, comparedwith CT, significantly increased the faba bean grain yield by 23%. The tillage systemhad no significant effect on soil NH3 emissions. Total N2O emissions, averaged over two cropping seasons, were higher inNT than those in CT plots (2.58 vs 1.71 kgN(2)O-Nha(-1), respectively; P < 0.01). In addition, DEAwas higher in NT compared to that in CT (74.6 vs 18.6 mu g N2O-N kg(-1) h(-1); P < 0.01). The higher N2O emissions in NT plotswere ascribed to the increase of soil bulk density and WFPS, bacteria (16S abundancewas 96% higher in NTthan that in CT) and N cycle genes (amoA and nosZ abundances were respectively 154% and 84% higher in NT than that in CT). The total N2O emissions in faba bean were similar to those measured in other N-fertilized crops. In conclusion, a full evaluation of NT technique, besides the benefits on soil characteristics (e.g. TOC increase) and crop yield, must take into account some criticisms related to the increase of N2O emissions compared to CT. (C) 2018 Elsevier B.V. All rights reserved.