Long-term nitrogen deposition inhibits soil priming effects by enhancing phosphorus limitation in a subtropical forest

It is widely accepted that phosphorus (P) limits microbial metabolic processes and thus soil organic carbon (SOC) decomposition in tropical forests. Global change factors like elevated atmospheric nitrogen (N) deposition can enhance P limitation, raising concerns about the fate of SOC. However, how elevated N deposition affects the soil priming effect (PE) (i.e., fresh C inputs induced changes in SOC decomposition) in tropical forests remains unclear. We incubated soils exposed to nine years of experimental N deposition in a subtropical evergreen broadleaved forest with two types of 13C-labeled substrates of contrasting bioavailability (glucose and cellulose) with and without P amendments. We found that N deposition decreased soil total P and microbial biomass P, suggesting enhanced P limitation. In P unamended soils, N deposition significantly inhibited the PE. In contrast, adding P significantly increased the PE under N deposition and by a larger extent for the PE of cellulose (PEcell..., This dataset was collected by sampling soils exposed to 9 years of manipulative N inputs in situ in a subtropical forest and then incubating them in a 30-day incubation experiment. The CO2 flux and PE were measured by NaOH trapping. Soil variables were measured at the end of incubation., Microsoft Office