Dataset: Tree functional traits drive the retention of deposited nitrogen and N-induced carbon sequestration

The impacts of nitrogen (N) deposition on forest carbon sequestration largely depend on N forms and their subsequent fates. While species mixing benefits carbon and N accumulation in plantation ecosystems, the fates of deposited N and their contributions to carbon sequestration in monoculture and mixed plantations in N-limited semiarid regions remain unclear. This dataset contains measurements from an ecosystem-scale ^15N labeling experiment conducted in monocultures of Robinia pseudoacacia, Pinus tabuliformis, and their mixed plantation on the Loess Plateau, China. Two forms of ^15N tracers—ammonium nitrate (^15N-AN) and urea (^15N-urea)—were applied to quantify the fate of deposited nitrogen in different plantation types. The dataset includes biomass, carbon and nitrogen concentrations, carbon and nitrogen pool sizes, and Δδ^15N values for major ecosystem compartments, including trees, understory vegetation, litter layer, and mineral soil. Data are provided in Microsoft Excel format (.xlsx) with clearly labeled sheets and columns. These data can support studies on nitrogen cycling, species mixing effects, and the fate of nitrogen deposition in plantation ecosystems.
Ecosystem compartments – The sampled component of the ecosystem, including tree organs (leaf, branch, bark, stem, coarse root, fine root), understory vegetation (herb and shrub, above- and belowground), litter layer, and mineral soil at 0–10 cm, 10–20 cm, and 20–40 cm depths. Prefixes indicate plantation type: RP = Robinia pseudoacacia monoculture, PT = Pinus tabuliformis monoculture, M_RP = R. pseudoacacia in mixed plantation, M_PT = P. tabuliformis in mixed plantation..
Δδ15N-AN (‰) – Change in δ15N values after 15N-ammonium nitrate labeling, expressed in per mil (‰) relative to natural abundance.
Δδ15N-urea (‰) – Change in δ15N values after 15N-urea labeling, expressed in per mil (‰) relative to natural abundance.