Dataset for 'Inorganic nitrogen nutrition in boreal plants is underestimated and insensitive to environmental changes' in Earth's Future

Although more and more evidences on plant uptake of soil inorganic N (IN) challenged the traditional viewpoint of soil organic N (ON) as the dominant (averaging 63±6%) N source to boreal plants, relative contributions between IN and ON to boreal plants and their environmental responses remain unclear. By investigating N concentrations and natural N isotopes in soils and plants, we evaluated and compared contributions of soil IN and ON to plants of six same genera between Alaskan tundra (AT) with lower mean annual temperature (MAT, -6.8℃) and atmospheric N deposition (AND, 0.4 kg-N/ha/yr) and northeastern China peatlands (NECP) with higher MAT (-3.3℃) and AND (5.1 kg-N/ha/yr). Soil IN was three times less than ON, but it contributed c.a. 54±7% of N among studied plants. In NECP, higher MAT and AND caused more increments (by three times) in soil ON than IN, but soil IN’s contributions to plants did not differ between AT (52±6%) and NECP (57±7%). We concluded that soil IN’s contributions to boreal plants are underestimated (by 17%) and insensitive to concurring warmer climates and higher N deposition, which is useful for evaluating ecosystem N dynamics and effects in boreal region.