Relative efficacy and stability of biological and synthetic nitrification inhibitors in a highly nitrifying soil: Evidence of apparent nitrification inhibition by linoleic acid and linolenic acid

Biological nitrification inhibition is a plant-mediated rhizosphere process where natural inhibitors can be produced and released by roots to suppress nitrifier activity in soil. Nitrification one of the critical soil processes nitrogen (N) cycle, but unrestricted rapid agricultural systems result major losses N from plant–soil system (i.e., NO3− leaching gaseous emissions). In this study, we explored potential efficacy biological (linoleic acid [LA] linolenic [LN]) proven efficient synthetic (dicyandiamide [DCD]) inhibitor on dynamics, nitrous oxide (N2O) carbon dioxide (CO2) emissions highly nitrifying 14C-labelled LA, LN DCD mineralization was determined parallel experiment explore fate after application. We found that LA had no effect NH4+ concentrations, significantly decreased concentrations. Soil received lower higher concentrations than control (soil without inhibitors). increased cumulative N2O CO2 when they were applied at high (635 or 1,270 mg kg−1 dry soil). much greater rate DCD: 47–56%, 37–61% 2.7–5.5%, respectively, 38 days incubation. conclude contrast direct caused DCD, addition may cause apparent promoting microbial immobilization and/or NO3−. Future studies need clearly differentiate between indirect effects these compounds Highlights The stability explored. This study supports efforts mitigate improve use efficiency inputs. Addition decrease concentration, their modes action different. concentration could indirect.