This data set contains aboveground plant biomass in 2010 (Sown plant community, Weed plant community, Dead plant material, and Unidentified plant material; all measured in biomass as dry weight) of the monoculture plots of a large grassland biodiversity experiment (the Jena Experiment). In the monoculture plots the biomass of the sown plant community contains only a single species per plot and this species is a different one for each plot. Which species has been sown in which plot is stated in the plot information table for monocultures (see further details below). The monoculture plots of 3.5 x 3.5 m were established for all of the 60 plant species of the Jena Experiment species pool with two replicates per species. One of the replicate plots per species was given up after the vegetation period of 2007 for all but the nine species belonging also to the so called dominance experiment in Jena. These nine species are: Alopecurus pratensis, Anthriscus sylvestris, Arrhenatherum elatius, Dactylis glomerata, Geranium pratense, Poa trivialis, Phleum pratense, Trifolium repens and Trifolium pratense.In 2010 plot size was reduced to 1 x 1 m. These 60 species comprising the species pool of the Jena Experiment belong to four functional groups (grasses, legumes, tall and small herbs). Plots were sown in May 2002 and are since maintained by bi-annual weeding and mowing. Aboveground plant biomass was harvested twice in 2010 just prior to mowing (during peak standing biomass in early June and in late August) on all experimental plots of the monocultures. This was done by clipping the vegetation at 3 cm above ground in 1 rectangle of 0.2 x 0.5 m per plot. The location of this rectangle was in the center of the plot area. The positions of the rectangles within plots were identical for all plots. The harvested biomass was sorted into categories: sown plant species, weed plant species (species not sown at the particular plot), detached dead plant material (i.e., dead plant material in the data file), and remaining plant material that could not be assigned to any category (i.e., unidentified plant material in the data file). All biomass was dried to constant weight (70°C, >= 48 h) and weighed.

The monoculture data belongs to the Jena Experiment data set representing all species sown in the main experiment on the field site of the Jena Experiment. There are two types of missing values contained in the dataset. Empty cells represent missing values that result from the design of the experiment when the respective value does not occur and could thus not be measured. For example, the columns of half of the cells are left blank since 2008 when on the plot replicates was given up. Missing values that resulted from methodological problems, sampling errors, or lost samples/data are marked with “-9999”.This datasets is part of a collection of time series of biomass measurements in the Jena Experiment since 2002 (doi:10.1594/PANGAEA.866358). Similar data from other experiments (e.g. Main Experiment, Dominance Experiment; see details above), other years, or other methods quantifying related data might be available in this collection.