This collection contains measurements of physical and chemical soil properties on 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.The following series of datasets are contained in this collection:1. Physical soil properties- Soil texture: Proportion of sand, silt and clay in the fine soil was measured in April 2002 before plot establishment at 27 locations distributed throughout the experimental site. Undisturbed soil cores were taken to 100 cm depth and separated in depth increments with a resolution of 10 to 20 cm. Grain size fractions according to DIN 19683-2 were then determined by a combined sieve and hydrometer analysis. Values for each plot were interpolated by ordinary kriging.- Bulk density: Bulk density was sampled down to 100 cm depth in 2002 and 30 cm depth in 2004, 2006 and 2008. Several undisturbed soil cores were taken per plot and separated in depth increments before the bulk material was sieved, dried and weighed.- Soil hydraulic properties: Field capacity and permanent wilting point at 10, 20 and 30 cm depth were derived from soil texture data of 2002 and bulk density 2006 by using pedotransfer functions. Applied was equation four and five of Zacharias and Wessolek (2007) to derive parameters of the water retention curve. Water contents at field capacity and permanent wilting point were obtained using the van Genuchte Eq (e.g. eq 1 in Zacharias and Wessolek), and calculating water contents at - 330 cm matric potential (field capacity, 1/3 of atmospheric pressure) and at -15000 cm.-Soil porosity: the fraction of total volume occupied by pores or voids measured at matric potential 0, already published on https://doi.pangaea.de/10.1594/PANGAEA.865254.2. Chemical soil properties- Lime content: Percentage of CaCO3 in the soil was measured in April 2002 before plot establishment at 27 locations distributed throughout the experimental site. Undisturbed soil cores were taken to 100 cm depth and separated in depth increments with a resolution of 10 to 20 cm. The bulk material was sieved and CaCO3 content of the fine soil was determined as volumetric determination according to DIN 19684-5.- Soil organic matter: Percentage of soil organic matter was measured in April 2002 before plot establishment at 27 locations distributed throughout the experimental site. Undisturbed soil cores were taken to 100 cm depth and separated in depth increments with a resolution of 10 to 20 cm. The bulk material was sieved and organic content of the fine soil was determined using a loss-on-ignition method.- Soil pH value: soil pH value was determined 2002 and 2010 in water and 2002 also in calcium chloride. Five soil samples were taken per plot and bulk material was diluted in water and calcium chloride. PH values were then measured with an electrode.

This data set is an ongoing collection of physical and chemical soil properties in the Jena Experiment. Please refer to the individual datasets below. Additional data might be available (more recent years). If you are interested in this data, please directly contact the authors via the Jena Experiment data manager [Hyperlink: http://www.the-jena-experiment.de/Contact.html].In case you want to cite this collection please use: "Yvonne Kreutziger, Jussi Baade, Gerd Gleixner, Maike Habekost, Anke Hildebrandt, Guido Schwichtenberg, Sabine Attinger, Yvonne Oelmann, Wolfgang W. Wilcke, Roeland Cortois, Gerlinde B. De Deyn, Guangjuan Luo, Sebastian T. Meyer (2017): Collection of data on physical and chemical soil properties in the Jena Experiment (Main Experiment), (https://doi.pangaea.de/10.1594/PANGAEA.885439) (downloaded [DATE])"