How tree species with contrasting biological nitrification inhibition capacity influence denitrifier activity and abundance? Insights from reciprocal transfers of soil


We evaluated whether and how rapidly temperate forest tree species able to stimulate or inhibit nitrification (through biological nitrification inhibition, BNI) also influence denitrifier activity and abundance in soil and identified the main determinants of changes in denitrification. A reciprocal soil core transfer approach was implemented at a long-term experimental site between Douglas fir, a species assumed to stimulate nitrification, and stands of tree species with (spruce and Nordmann fir) or without (Corsican pine and beech) BNI capacity. Sixteen months after soil transfer, potential denitrification decreased in soils transferred from Douglas fir to another tree species and increased in soil cores transferred from any species to Douglas fir. The change in denitrification was not related to the BNI capacity of the tree species ‘receiving’ the soil cores. Structural equation modelling revealed that in soil cores transferred between Douglas fir and BNI species, changes in denitrification were mainly correlated to nitrifier abundances, i.e. AOA and Nitrobacter, nitrification rates, and soil N­ O3− availability, whereas in soil cores transferred between Douglas fir and non-BNI species denitrification changes were well correlated to C availability and the abundance of nirK-harbouring denitrifiers. Overall, our results indicate that denitrification rates can change strongly and quickly following soil transfers between tree stands. Particularly, when Douglas fir replaces BNI tree species, this quickly results in both increased nitrification and denitrification rates, thus exacerbating the ensuing risk of increased ­NO3− leaching and ­N2O emission from soil.

Auteurs, date et publication :

Auteurs A. Florio , C. Bréfort , C. Creuze des Chatelliers , J. Gervaix , F. Poly , B. Zeller , X. Le Roux

Publication : Biology and Fertility of Soils

Date : 2023

Volume : 57

Issue : 8

Pages : 1089-1101