The aim of the study was to investigate the influence of fertilizers on root-associated and soil residing fungi in beech forests. We report data from a fertilization experiment in three temperate beech forest with contrasting soil phosphorus concentrations. We used soil cores and the fractions of the organic layer and mineral topsoil separately of spring and fall 2018. We collected bulk soil and roots. We provide data on soil for pH, mineral elements, ammonium, nitrate, carbon, nitrogen. We provide data on root mineral nutrients, carbon and nitrogen. Illumina sequencing in soil and roots provides fungal amplicon sequence variant (ASV) and morphotyping of beech fine roots the active colonizing ectomycorrhizal fungi, including diversity parameters.

Plots were installed in beech (F. sylvatica L.) forests in three areas that differ in soil properties: Bad Brückenau (50°21'7.2"N 9°55'44.5"E, 801 to 850m a.s.l.), a high-P (HP), Mitterfels (48°58'34.1"N 12°52'46.7"E), a medium-P (MP) and Luess (52°50'21.7"N 10°16'2.3"E, 115 m a.s.l.), a low-P (LP) site.

For this study, twelve plots were installed in the forests in Fall 2016. Each plot had an area of 400 m². Four different fertilization treatments were used: control, N, P, P+N, with three replicates at each site.

Phosphorus (P) was applied once in fall 2016 as KH2PO4 at the dosage of 50 kg P ha-1 to the P and N+P plots. Nitrogen (N) was applied as NH4NO3 five times (fall 2016, spring 2017, summer 2017, fall 2017, spring 2018) corresponding to a dosage of 30 kg N ha-1 per treatment on the N and N+P plots.
Samples were taken in spring and fall 2018.