Data from: Tree species rather than type of mycorrhizal association drives inorganic and organic nitrogen acquisition in tree-tree interactions

A field study was conducted to evaluate the effects of associated
mycorrhization type on tree-tree interactions using the framework of the
MyDiv tree diversity experiment established at the Bad Lauchstädt
Experimental Research Station of the Helmholtz Centre for Environmental
Research (UFZ) (Saxony-Anhalt, Germany). Inorganic and organic net N
uptake capacity was quantified in fine roots of AM (i.e. Acer
pseudoplatanus L., Fraxinus excelsior L., and Prunus avium L.) as well as
EM associated tree species (i.e. Carpinus betulus L., Fagus sylvatica L.,
and Tilia platyphyllos Scop.) using 15N/13C isotopes. Trees grew either in
monocultures or 2-species mixtures, either only ectomycorrhizal, only
arbuscular mycorrhizal, or in combination. Generally, ammonium was
preferred over glutamine and glutamine over nitrate. Inorganic and organic
N sources were not used complementarily depending on a species´
mycorrhizal association, but their uptake rather depended on the
competitor indicating species-specific effects. At the species level,
inorganic and organic N acquisition differed among the studied tree
species. N acquisition within tree species changed N source-specific
depending on the competitor.