This dataset includes soil mass, organic phosphorus, carbon and nitrogen concentrations for light and heavy fractions, obtained from soils collected from UK habitats. The dataset includes 20 soils, collected from the Ribble, Avon and Conwy catchments in the North West, South and North Wales respectively. Samples were split into light and heavy fractions using a physicochemical fractionation method. The dataset also includes recoveries of carbon, nitrogen and phosphorus as a measure of the efficacy of the fractionation method. Extra data on sampling location, catchments conditions and bulk soil texture are also included in this dataset.