Nitrous oxide productivity of soil fungi along a gradient of cattle impact

•Eighty out of 164 fungal isolates (48.8%) were considered as N2O producers.•33 fungal species of 23 different genera exhibited N2O producing activity.•N2O production was newly reported in various fungal genera.•Highly productive fungi were isolated from soils under current cattle impact.•N2O-producing fungi are common constituent part of biota in cattle-impacted soils.

The objective of the study was to identify N2O-producing fungi isolated from six qualitatively different sections of an overwintering pasture with substantial cattle impact. 80 out of 164 fungal isolates were considered as N2O-producers in nitrite-containing medium, representing 33 fungal species of 23 different genera. Ability to produce N2O was newly reported in eight genera: Arthrinium, Gibellulopsis, Ilyonectria, Lichtheimia, Paraphaeosphaeria, Purpureocillium, Tolypocladium and Westerdykella. Three levels of fungal N2O-productivity were assigned according to the fraction of nitrite-N transformed into N2O–N: < 1%, 1–10%, over 10%. Fungi capable of high and moderate transformation rates were predominantly isolated from sections under current or past cattle impact, where they contributed with a maximum of 65% of the total N2O emissions. There was no significant effect of cultivation conditions on the fraction of N2O-producing fungi. The results demonstrate that N2O-producing fungi are a common constituent of fungal communities in soils impacted by overwintering cattle.