Empirical and modelled data from a model investigation into the consequences of nitrogen (N) deposition and nutrient manipulation on carbon (C) and nutrient cycling in phosphorus (P)-limited grasslands. Empirical data show above-ground biomass C, soil organic C and total soil N from two grassland types at Wardlow Hay Cop in the Peak District national park, UK. Wardlow is a long-term nutrient manipulation experiment (> 25 years) investigating the consequences of N deposition on grassland ecosystems. These data were collected during the summer of 2019 and were combined with total soil P data collected previously to form a dataset for inclusion in a CNP biogeochemical cycling model; N14CP. We use these empirical data to drive and calibrate the N14CP model in order to develop our understanding of the C, N and P dynamics of the two grasslands. Specifically, we investigate how potential differences in organic P cycling between the two grassland types may explain their contrasting responses to long-term N deposition and further experimental treatments. Accordingly, the bulk of this dataset is modelled data derived from the empirical data, and relates to the responses of plant C, soil C, N and P to N deposition and nutrient manipulation. This includes data on the CNP budgets of the modelled grasslands, P-cycling parameters used within the model, comparisons of empirical to modelled data, and changes in CNP pools resulting from N deposition and nutrient manipulation. Full details about this nonGeographicDataset can be found at https://doi.org/10.5285/98b473c7-3ca9-498d-a851-31152b1f1da7

The dataset contains information from 234 trees at six sites across the UK collected in 2018. The tree species studied were Acer pseudoplatanus (sycamore), Castanea sativa (sweet chestnut), Fagus sylvatica (beech), Fraxinus excelsior (common ash), Quercus cerris (Turkey oak), Q. petraea (sessile oak), Q. robur (pedunculate oak), Q. rubra (red oak) and Tilia x europaea (common lime). The presence of all lichens and bryophyte species on the trunk to a height of 1.75m were recorded in addition to the presence of the lichens on branches and twigs where these were accessible. The bark characteristics recorded were bark pH, ridge and furrow width, furrow depth, hardness, water holding capacity and the bark patterning. The soil variables studied were: nitrogen mineralization and decomposition rate, total soil carbon and nitrogen, loss on ignition, soil pH and soil temperature. Fourier-transform infrared (FTIR) spectroscopy data from the soil samples is also presented along with data on site location and the habitat characteristics surrounding the sampled trees. Full details about this dataset can be found at https://doi.org/10.5285/f539567f-a8cd-482e-89b8-64a951b52d93