This dataset contains carbon and nitrogen stock data from soils collected from Salisbury Plain, UK. The sites were selected to reflect the four main grassland management types on Salisbury Plain ranging from arable cropland to species rich grassland, with six representative grassland plots for each type (24 sites in total). Each site had two replicates for each variable measured. The data collected was intended to illustrate a gradient of ecosystem functioning and vegetation change as the grassland becomes more extensively managed. The field sampling was conducted by the University of Manchester and the Centre for Ecology & Hydrology at Wallingford. Soil C and N were analysed by the University of Manchester. The data includes carbon and nitrogen budgets to depth at all sites.