Evidences towards deciphering the mode of action of dimethylpyrazole-based nitrification inhibitors in soil and pure cultures of Nitrosomonas europaea

Abstract Background Agriculture relies on the intensive use of synthetic nitrogen (N) fertilizers to maximize crop yields, which has led transformation agricultural soils into high-nitrifying environments. Nevertheless, nitrification inhibitors (NIs) have been developed suppress soil-nitrifier activity and decrease N losses. The NIs 3,4-dimethylpyrazole phosphate (DMPP) 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (DMPSA) are able reduce 2 O emissions maintain soil NH 4 + for a longer time. Although both proven be effective inhibit nitrification, their exact mode action not confirmed. We aimed provide novel insights further understand DMP-based NIs. evaluated performance DMPP DMPSA in pure cultures nitrifying bacteria Nitrosomonas europaea . Results did N. In soil, we evidenced that needs broken DMP achieve inhibition is mediated by biological process remains identified. Moreover, thought due ability chelate Cu 2+ cations ammonia monooxygenase enzyme (AMO) carry first step oxidation. However, efficiency was altered regardless concentration medium. addition, also showed targets AMO but hydroxylamine oxidoreductase (HAO). Conclusions inability together with high even presence toxic medium, suggest does rely capacity as metal chelators. Graphical