DOI: 10.5285/98b473c7-3ca9-498d-a851-31152b1f1da7
title: Empirical and modelled carbon, nitrogen and phosphorus content of plants and soils from Wardlow Hay Cop, UK

description: 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.


description: Empirical data:
Above ground biomass carbon was determined from the dry weight of a sward harvest for each nutrient treatment and in both grasslands. Soil organic C and total soil N was determined by acid stripping dried soil to remove carbonates and then analysing it in an isotope-ratio mass spectrometer. Total soil P was taken from previous research at Wardlow. These data were converted into model-compatible units (grams per metre squared) prior to their use in the modelling study. Plant C and soil C and N was collected from all four nutrient treatments; a distilled water control, a low nitrogen (3.5 g N m-2 yr-1) a high nitrogen (14 g N m-2 yr-1) and a phosphorus addition (3.5 g P m-2 yr-1). Total soil P data was only available for the control and high nitrogen treatments.

Modelled data:
These data were used to calibrate two P-cycling parameters within the N14CP model in order to simulate the nutrient manipulation experiment within the model. After assessing the model’s performance using the empirical data, we investigated the consequences of long-term N deposition and nutrient manipulation on the C, N and P pools of soil and the above ground biomass C pool. All modelled data is in grams per metre squared unless stated otherwise in the metadata. Some modelled data, notably the timeseries, spans the years 1800 – 2020 in order to model changes on longer timescales. Note that the empirical data relates only to the year 2019 in which it was collected, which represents 24 years of experimental nutrient addition.