The dataset provides information about the soil chemical properties at two permanent LTER sites (named site 1 and 3, according to the LTER site numerations). The investigated period is 2008-2020. Details: Site 1 (coordinates: 45°52'22.43"N, 7°52'25.84"E; elevation: 2840 m a.s.l.) and Site 3 (coordinates: 45°52'13.52"N, 7°52'35.01"E; elevation: 2770 m a.s.l.). The bedrock is primarily micaschists, with some inclusions of amphibolites and calcschists. The vegetation of the sites is included in the ‘Siliceous alpine and boreal grasslands’ (habitat 6150, according to the EU Habitat Directive). At each site, consisting of paired plots for soil and vegetation survey, three 9 m2 plots are established, where three topsoil samples (A horizon, 0–10 cm depth) are collected annually at the end of the snow-free season (September). On soil samples the following analysis are performed: N-NH4, N-NO3, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), dissolved organic nitrogen (DON), microbial carbon (Cmicr), and microbial nitrogen (Nmicr).