This dataset has been used to establish reference values for organic matter production and nitrogen uptake of ten common monoculture cover crops. It contains cover crop data from several experiments and years of sampling. Most entries contain data on aboveground or belowground biomass. Later entries also contain data on macro- and micronutrient contents. For some entries the soil mineral nitrogen is available. It is possible that additional meta-data and data from other variables can be found if needed. Data used in the report from the 'Clever cover cropping' experiment was excluded from this dataset. A new dataset (containing this and new data) will be published after 2 years.