Moisture: binary variable indicating whether a plot was located in a relic floodplain channel with slightly higher soil moisture due to a periodically elevated groundwater table [moist] or not [normal] Soil_depth: distance between soil surface and calcareous gravel bedrock [cm] Texture: nominal variable indicating soil texture [uL, silty loam; hsL, humic sandy loam; sL, sandy loam; hstlS, humic strongly loamy sand; stlS, strongly loamy sand; hwlS, humic weakly loamy sand; wlS, weakly loamy sand] pH: soil pH Mg: soil concentration of Magnesium ions [mg/l] P2O5: soil Phosphorus concentration, measured in P2O5 equivalents [mg/kg] K2O: soil Potassium concentration, measured in K2O equivalents [mg/kg] NO3: soil concentration of Nitrate ions [mg/l] NH4: soil concentration of Ammonium ions [mg/l] N: total soil nitrogen concentration [mg/kg]