Conspecific and heterospecific plant-soil feedback data and root trait measurements of 18 annual and perennial plant species

These two data sets contain the raw data of an experimental project in which we aimed to unravel the drivers of plant-soil feedback interactions among annual and perennial grassland plant species. In our two-phase greenhouse experiment, we first conditioned field soil with 18 different annual and perennial plant species. In this conditioning phase, plants grew for 11 weeks until they were harvested and were regularly watered. The biomass data of that conditioning phase can be found in the first tab (Conditioning phase) of 'Wilschut_etal_biomass.xlsx'. For each conditioning phase plant species, there were 20 pots planted with single seedlings, with 4 pots in each experimental block. At the end of the first phase, soils from 3 out of 4 pots were combined into one soil bag, serving as inoculum for the feedback phase. This was done as some of the plants died during the conditioning phase. Shoot and root biomass of conditioning plants of the selected pots were separately measured. In the second tab (Feedback phase) of 'Wilschut_etal_biomass.xlsx' root and shoot biomass data of all 18 plant species in all different soils from the conditioning phase can be found. In this phase, plants grew for 8 weeks, were regularly watered and received 60 ml of a 1% Universol^® Blue fertilizer solution at the start of the growth period. Initial leaf numbers of the seedlings are also reported. In 'Wilschut_etal_roottraits.xlsx', structural root trait data of all 18 plant species are listed. These data were measured in a separate greenhouse experiment, in which we seperately grew single plant individuals (N = 3) of each species in a mixture of sand-vermiculite. Each pot in total received 160 ml of a 1% Universol^® Blue fertilizer solution during the 7-week growth period. After that, we washed and scanned root systems and obtained root length and average root diameter measurements using WhinRHIZO software (Pro version 2017a; Regent Instrumentals Canada Inc.). Root and shoots were weighed to also obtain specific root length and relative root weight measurements.