Plant species identity and arbuscular mycorrhizal status modulate potential nitrification rates in nitrogen‐limited grassland soils

摘要: Summary 1. Arbuscular mycorrhizal (AM) fungi and ammonia oxidizers (AO) represent key soil microbial groups regulating nitrogen (N) cycling in terrestrial ecosystems. Both utilize ammonium-N reserves for N assimilation, whilst the latter, through autotrophic nitrification, drive oxidation to highly mobile nitrate-N. 2. An incompatible interaction between root symbiotic AM AO was hypothesized evaluated plant–species-rich, N-limited Mediterranean grassland soils. Such an outcome would be manifested a negative relationship plant mycotrophy local potential nitrification rates (PNR), standard functional measure of ammonia-oxidizing activity soils. 3. In three independent mesocosm experiments, soils that supported monocultures mycotrophic, as opposed weakly non-mycotrophic, plants exhibited significantly lower PNR. Under field conditions fourth experiment, we verified from stands mycotrophic Agrostis capillaris sustained higher PNR than counterparts supporting Prunella vulgaris Fragaria vesca. 4. Discussion mycotrophy-related modulation centres on whether observed relationships highlight evidence either direct competition or functionally important example plant–microbial allelopathy. 5. Synthesis. Substantial has been presented confirming (i) species identity-related regulation (ii) species-mediated impact Likely mechanisms (i.e. and/or allelopathy) underpin this significant plant–microbe–soil controlling fate require urgent elucidation N-deficient