Contrasting effects of nitrogen addition on rhizosphere soil CO2, N2O, and CH4 emissions of fine roots with different diameters from Pinus tabulaeformis forest using laboratory incubation

Abstract Nitrogen (N) addition has variable effects on chemical composition, function, and turnover of roots with different diameters. However, it is unclear whether N addition has variable effects on greenhouse gas (GHG) emission in rhizosphere soil. We performed N addition (0–9 g N m−2 y−1) experiment in a Pinus tabulaeformis forest and a lab-incubation experiment to determine the effects of N addition on carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions in rhizosphere soils of roots with different diameters (very fine roots: