This data set contains measurements of lime content in the soil, i. e. percentage of CaCO3. Data presented here is from the Main Experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained in general by bi-annual weeding and mowing. Since 2010, plot size was reduced to 5 x 6 m and plots were weeded three times per year.
Lime content was determined from undisturbed soil cores at 27 locations distributed throughout the experimental site in spring 2002 before plot establishment. Two of the locations are now reference plots and thus not included in this data set. Soil cores were taken to 100 cm depth and separated in depth increments with a resolution of ten cm from ground level to 40 cm depth and 20 cm from 40 cm to 100 cm depth. The bulk material was passed through a sieve with 2 mm mesh size and only fine soil was used for the investigation of lime content. Percentage of CaCO3 for every sample was then determined at the laboratory for geoecology of Jena University as volumetric determination according to DIN 19684-5.
