Soil pH value from the Jena Experiment (Main Experiment, year 2002)

This data set contains measurements of soil pH values. 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.
In 2002, soil pH values were determined in both, water and calcium chloride. Five soil samples with a diameter of 1 cm per plot were taken to 30 cm depth and separated in increments of 0-15 and 15-30 cm. Soil was diluted in H2O and CaCl2 with a ratio of 1:2.5 of soil to solution and pH value was measured with an electrode (Knick pH Meter 761 Calimatic).