Nonlinear responses of total belowground carbon flux and its components to increased nitrogen availability in temperate forests

摘要: Abstract With the increased interest in allocating more carbon (C) belowground for C sequestration, total flux (TBCF) and its dynamics have become an important research topic. However, it remains uncertain whether TBCF responds nonlinearly to nitrogen (N) availability how main components (root ectomycorrhizal (ECM) fungi) contribute TBCF. We established a four-year N addition experiment with control, low-N, medium-N, high-N fertilization treatments N-limited temperate forest northern China. measured three including root respiration, ECM fungal production. The involved edaphic plant factors were also measured. showed nonlinear response increasing amounts of N addition, accelerated by 10.37% low-N restrained 10.29% addition. Contrasting patterns contributions respiration implies different strategies investment roots fungi under N-availability statuses. ratio production was nearly 1:2, which indicated that when soil increases, prefer lose overflow rather than fix new biomass. directly indirectly coarse medium-N positively affected but this positive effect cancelled out significantly negative concentration. decrease pH most effective pathway Because large-scale reforestation program sink management recent years, our findings could provide insight predicting sequestration potential atmospheric deposition.