Description: This data set contains measurements of morphological root parameters, i.e. length and diameter of newly built roots. 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). Since 2010, plots were weeded three times per year. In June 2003, five soil cores with a 4.8 cm diameter per plot were taken to 30 cm depth. The removed soil was replaced by root-free soil from the field site. In September 2003, the initially root-free ingrowth cores were removed and the holes were refilled with root-free soil until the following withdrawal in July 2004. To extract the newly formed roots, each ingrowth core was first weighed and carefully homogenized. A subsample of 50 g of soil was suspended in water and rinsed over a 0.5 mm screen. Roots collected in the screen were transferred into a water-filled clear acrylic tray and scanned. Total root length and mean diameter were determined by using WinRhizo (Regent Instruments, Quebec, Canada). Afterwards, root length density (cm root length per cm3 soil volume) was calculated.

Description: This data set contains measurements of diameter of standing roots. 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, plots were weeded three times per year. In September 2004, three soil cores with a 4.8 cm diameter per plot were taken to 30 cm depth. The bulk material of the pooled cores was cut with scissors to 〈 1 cm pieces. A subsample of 50 g was suspended in water and rinsed over a 0.5 mm screen. Roots collected in the screen were transferred into a water-filled clear acrylic tray and scanned. Mean diameter of the roots was determined by using WinRhizo (Regent Instruments, Quebec, Canada).

Description: This data set contains measurements of belowground biomass productivity, i.e. coarse and fine root biomass production (C- and N-concentration of the fine roots are attached to this dataset as well). 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, plots were weeded three times per year. In June 2003, five soil cores with a 4.8 cm diameter per plot were removed to 30 cm depth. The removed soil was replaced by root-free soil from the field site. The ingrowth cores were removed in September 2003 and cut with scissors until root fragments were 〈 1 cm in length. For root washing, a 50 g subsample of the bulk material was taken and soaked in water. The soil was removed from the roots by rinsing over a sieve with 0.5 mm mesh width. Then, organic debris and remaining soil particles were removed by hand. The remaining roots were dried at 70 °C and weighed. In 2003, roots were seperated in coarse (diameter 〉 2 mm) and fine roots after root washing. After withdrawal of the ingrowth cores in September 2003, the holes were refilled with root-free soil, and the ingrowth cores were sampled again in July 2004. In 2003 and 2004, fine roots were grinded in a ball mill and 20 mg of the grinded material was used to determine C- and N-concentration of the fine roots with VarioMax CNS (Elementar).

Description: This data set contains measurements of belowground biomass productivity, i.e. coarse and fine root biomass production (N-concentration of the fine roots are attached to this dataset as well). 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, plots were weeded three times per year. In July 2007, five soil cores with a 4.8 cm diameter per plot were removed to 30 cm depth. The removed soil was replaced by root-free soil from the field site. The ingrowth cores were removed in June 2008 and cut with scissors until root fragments were 〈 1 cm in length. For root washing, a 210 g subsample of the bulk material was taken and soaked in water. The soil was removed from the roots by rinsing over a sieve with 0.5 mm mesh width. Then, organic debris and remaining soil particles were removed by hand. The remaining roots were dried at 70 °C and weighed. In 2008, ingrowth cores were separated in depth increments of 0-5, 5-10, 10-20 and 20-30 cm depth. Roots were seperated in coarse (diameter 〉 2 mm) and fine roots before cutting the bulk material. Fine roots were grinded in a ball mill and 20 mg of the grinded material was used to determine N-concentration of the fine roots with VarioMax CNS (Elementar).

Description: This data set contains measurements of standing belowground plant biomass. 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, plots were weeded three times per year. In 2004, standing root biomass was sampled in September. Three soil cores with a 4.8 cm diameter per plot were taken to 30 cm depth and pooled plot-wise. The cores were immediately stored cool until further handling. The bulk material of the pooled cores was weighed and cut with scissors to 〈 1 cm pieces. For root washing, a 50 g subsample was soaked in water and then repeatedly rinsed with tap water over a 0.5 mm sieve. Remaining soil particles were removed by hand. Roots were dried at 60 - 70 °C and weighed subsequently. In 2004, roots were seperated in coarse (diameter 〉 2 mm) and fine roots after root washing.

Description: This collection contains measurements of standing below ground biomass, belowground biomass productivity and morphological root parameters measured 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). Since 2010, plots were weeded three times per year. The following series of datasets are contained in this collection: 1. Standing below ground biomass: Coarse and fine root biomass was measured in 2003, 2004, 2006 and 2008 in 0 - 30 cm depth. In 2011 and 2014, total root biomass was sampled down to 40 cm depth. Some years report the data divided into sublayers. Every year, several soil cores were taken per plot and pooled before the whole bulk material or a subsample was washed for roots. Roots were dried at 60 - 70 °C and weighed. Standing root biomass was calculated as g m-2. 2. Below ground biomass productivity in 0 - 30 cm depth: Coarse and fine root biomass production from June to September 2003, September 2003 to July 2004 and July 2007 to June 2008 was measured by the ingrowth core method. In 2008, the data is reported divided into sublayers. Each time, five soil cores were taken per plot and replaced by root free soil from the field site. The initially root-free ingrowth cores were removed after a while and pooled plot-wise. To extract the newly formed roots, a subsample of the bulk material was washed for roots. Roots were dried at 70 °C and weighed. Root biomass productivity was calculated as g m-2. In addition, C- (only in 2003 and 2004) and N-concentration of the fine roots was determined. 3. Morphological root parameters of newly formed roots in 0 - 30 cm depth: Root length density and mean root diameter of newly formed roots from June to September 2003 and September 2003 to July 2004 were measured by the ingrowth core method. Each time, five soil cores were taken per plot and replaced by root free soil from the field site. The initially root-free ingrowth cores were removed after a while and pooled plot-wise. To extract the newly formed roots, a subsample of the bulk material was washed and scanned. Root length and mean diameter were determined by using WinRhizo (Regent Instruments, Quebec, Canada). 4. Morphological root parameters of standing roots in 0 - 30 cm depth: In 2004, mean diameter of standing roots was measured by sampling three soil cores per plot. To extract the standing roots, a subsample of the bulk material was washed and scanned. Mean diameter was determined by using WinRhizo (Regent Instruments, Quebec, Canada).

Description: This data set contains measurements of standing belowground plant biomass. 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, plots were weeded three times per year. In 2003, standing root biomass was sampled in June. Five soil cores with a 4.8 cm diameter per plot were taken to 30 cm depth and pooled plot-wise. The cores were immediately stored cool until further handling. The bulk material of the pooled cores was weighed and cut with scissors to 〈 1 cm pieces. For root washing, a 50 g subsample was soaked in water and then repeatedly rinsed with tap water over a 0.5 mm sieve. Remaining soil particles were removed by hand. Roots were dried at 60 - 70 °C and weighed subsequently. In 2003, roots were seperated in coarse (diameter 〉 2 mm) and fine roots after root washing.

Description: This data set contains measurements of standing belowground plant biomass. 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, plots were weeded three times per year. In 2006, standing root biomass was sampled in June. Five soil cores with a 8.7 cm diameter per plot were taken to 30 cm depth and pooled plot-wise. The cores were immediately stored cool until further handling. The bulk material of the pooled cores was weighed and cut with scissors to 〈 1 cm pieces. For root washing, a 210 g subsample was soaked in water and then repeatedly rinsed with tap water over a 0.5 mm sieve. Remaining soil particles were removed by hand. Roots were dried at 60 - 70 °C and weighed subsequently. Roots were seperated in coarse (diameter 〉 2 mm) and fine roots after root washing.

Description: This data set contains measurements of standing belowground plant biomass. 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, plots were weeded three times per year. In 2008, standing root biomass was sampled in June. Three soil cores with a 4.8 cm diameter per plot were taken to 30 cm depth and pooled plot-wise. The cores were immediately stored cool until further handling. The bulk material of the pooled cores was weighed and cut with scissors to 〈 1 cm pieces. For root washing, a 210 g subsample was soaked in water and then repeatedly rinsed with tap water over a 0.5 mm sieve. Remaining soil particles were removed by hand. Roots were dried at 60 - 70 °C and weighed subsequently. In 2008, soil cores were separated in depth increments of 0-5, 5-10, 10-20 and 20-30 cm depth and the corresponding layers were pooled plot-wise. Roots were seperated in coarse (diameter 〉 2 mm) and fine roots before cutting the bulk material.