Responses of Alpine Soil Nitrification and Denitrification Rates to Nitrogen Addition Gradient—The Role of Functional Genes

Increases in nitrogen (N) deposition affect the nitrification and denitrification processes that are regulated by microorganisms. With aim of understanding what happened to soil rates under N application gradients, we set a field experiment treated with at 6 different (0, 2, 4, 8, 16, 32 g N·m−2·yr−1) 2014. We determined physico-chemical properties, abundances community structures nitrifiers denitrifiers, net rate (NNR) potential (PDR) samples were collected 2020. found ammonia-oxidizing bacteria amoA (AOB amoA), sum archaea (AOA amoA) AOB increased increase rate, but nosZ decreased that. The microorganisms dominate ammonia oxidation process could shift from AOA high rates. Furthermore, respond addition preferentially abundance changes rather than composition changes. Moreover, NNR input, while decrease PDR was due pH value caused application. results also showed gene explained most (46.3%) variation NNR. moisture 44.0% 27.1% PDR, respectively. demonstrated mainly functional genes environmental factors, respectively, alpine meadow sustained deposition.