Biogeochemical nitrogen properties of forest soils in the Japanese archipelago

This data paper provides some biogeochemical nitrogen (N) properties and related chemical properties of forest soils from 39 sites throughout the Japanese archipelago. The data set was collected and analyzed under the GRENE (Green Network of Excellence) environmental information project and the ReSIN (Regional and comparative Soil Incubation study on Nitrogen dynamics in forest ecosystems) project. The sites cover 44°20′N to 26°50′N and the climate ranges from cool-temperate zone to subtropical zone. At each site, litter on forest floor and soil samples (three or four layers to 50 cm depth) were collected between August and November in 2010–2013 from five soil profiles. From the litter layer samples, the stocks and concentrations of total carbon (C) and N were measured. From the mineral soil samples, bulk density, pH (H₂O), total C and N concentrations, net and gross rates of N mineralization, nitrification and concentrations of water-soluble substances were measured. The measurements are relevant for other biogeochemical N studies in forest ecosystems and the data set provides basic information on the N pool and fluxes with related chemical properties of forest soils across the Japanese archipelago. The average rates of net and gross N transformation at 20 °C across the sites were 0.26 ± 0.47 mgN kg⁻¹ soil d⁻¹ for net N mineralization, 0.25 ± 0.45 mgN kg⁻¹ soil d⁻¹ for net nitrification, 4.06 ± 0.47 mgN kg⁻¹ soil d⁻¹ for gross N mineralization, and 1.03 ± 1.29 mgN kg⁻¹ soil d⁻¹ for gross nitrification (average ± SD).