General soil chemical, physical and microbial properties are presented for soil samples at six depths collected from a field experiment in the Conwy catchment. Samples were collected in May 2015. Core samples were taken along three transects by trained members of staff the Centre for Ecology & Hydrology and Bangor University. General soil chemical, physical and microbial properties were measured at six depths by trained members of staff, using recognised procedures at the laboratories of the School of Environment, Natural Resources and Geography, Bangor University. The samples were taken to provide supporting information for assessing the relationship between soil microbial populations and soil properties. The data were collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/f7b2beaa-08cf-48db-9b07-c55118d11506

The data comprise water quality measurements taken from streams and rivers in the Conwy catchment and its estuary from March 2013 to October 2016. Depending on water type and sampling location the data consist of concentrations of major cations and anions, pH, conductivity, alkalinity, suspended material and coliforms. Samples were collected manually or by automatic sampler. Analysis was carried out at the Centre for Ecology & Hydrology (CEH) Bangor, CEH Lancaster and Bangor University laboratories. The data were collected provide information on the relationship between stream water quality, primarily macronutrient concentrations, and catchment and hydrological characteristics. The data are used to drive a catchment scale water quality model, and to investigate nutrient ratios and limitation with respect to land cover and management. All sampling and analysis was carried out by trained members of staff from the Centre for Ecology & Hydrology and Bangor University. This data was assembled under the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (Turf2Surf). Full details about this dataset can be found at https://doi.org/10.5285/32392c33-8cbe-434a-a582-ab8425a5062c

The data consist of soil carbon in kilogrammes (kg) of carbon per metre squared. Soil cores were taken to a depth of 1 metre and divided into 15 cm depth increments. Soil carbon (kg carbon per metre squared) was determined for all soil depth increments. The soil samples were taken in the Conwy catchment in North West Wales. Samples were collected in the spring of 2014 across a land use intensification gradient ranging from semi-natural peatlands, acid grasslands to improved grasslands and arable fields. Soil parameters were tested across a land use intensification gradient to detect parameters that can predict aboveground biomass production across different land management types. Data were used to enhance the predictions of biomass production in the Joint UK Land Environment Simulator model (JULES). Measurements informed the improvement of the nitrogen cycle component in the model. This dataset is part of a data series where plant and soil measurements were collected together to increase our understanding of coupled aboveground and belowground processes. Measurements were undertaken by trained members of staff from Bangor University, the Centre for Ecology & Hydrology and Exeter University. This data was collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/dd6835bf-9c7e-4ad6-95f2-d15f24162fb3

The data consists of plant physiological measurements from 15 sites located in the Conwy catchment (North Wales) and from 2 sites in North West England. Plant photosynthetic parameters for the maximum rate of carboxylation (Vcmax), the maximum rate of electron transport (Jmax) and the maximum light saturated photosynthesis (Asat) were measured on the dominant plant species as were foliar nitrogen (Foliar N) and phosphorus (Foliar P). Leaf mass area (LMA) and specific leaf area (SLA) were recorded on the same leaves. Data were collected in 2013, 2014 and 2016. The sites were chosen to represent habitat types and the terrestrial productivity gradient in Britain from intensive agriculturally managed lowland grasslands through to montane heath. Plots within the sites were located using a stratified random sampling design. Plant parameters were tested across a land use intensification gradient to detect parameters that can predict aboveground biomass production across different land management types. Data were used to enhance the predictions of biomass production in the Joint UK Land Environment Simulator model (JULES). Measurements informed the improvement of the nitrogen cycle component in the model. Measurements were undertaken by trained members of staff from Bangor University, the Centre for Ecology & Hydrology and Exeter University. This data was collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/a9226e79-d4da-4d4d-bd39-3a6b4a7a327d

Time series data of carbon release in disintegrations per minute are presented for different nitrogen and phosphorus treatments with a low glucose concentration substrate added as a carbon source to soil samples from six depths (0-15, 15-30, 50-100, 100-150, 150-200 and 250-300 centimetres). Soil cores were collected from a field experiment in the Conwy catchment in July 2016 and returned the laboratories of the School of Environment, Natural Resources and Geography, Bangor University. A high molecular weight substrate was added as a carbon source to the samples and the rate of 14C-substrate mineralization measured. All the work was carried out by trained members of staff from Bangor University and the Centre for Ecology & Hydrology. The measurements were taken to improve understanding of the relationship between microbial activity and soil properties and depth of sampling, under differing nutrient availability. The data were collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/c29d2ce1-0295-439b-adf1-98ed59f73fae

Data are presented showing grass productivity as grammes per 100 square centimetres under four different nutrient treatments (water, nitrogen, phosphorus and nitrogen & phosphorus combined). An experimental hillslope in the Conwy catchment was selected in August 2016. Three transects, were identified across the hillslope. Along each transect, a 1 x 1 square metre quadrat was used to delineate randomly selected sampling areas. Within each quadrat 5 individual 10 x 10 x 10 centimetre (cm) swards were collected using a spade and transported to the laboratory in Bangor University for the nutrient addition. Three different harvests at different stages (initial cut, first harvest, second harvest) were conducted in order to measure grass productivity. Harvest included removal of all vegetation within the quadrat down to approximately 1 cm in height. The data were collected to identify the nutrient limitations within the hillslope by trained members of staff from Bangor University and the Centre for Ecology & Hydrology. The data were collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/6e395915-ab5c-43f4-b4de-c9a3c5c1b956

Time series data of carbon release in disintegrations per minute are presented for different nitrogen and phosphorus treatments with a high molecular weight substrate added as a carbon source to soil samples from six depths (0-15, 15-30, 50-100, 100-150, 150-200 and 250-300 centimetres). Soil cores were collected from a field experiment in the Conwy catchment in July 2016 and returned the laboratories of the School of Environment, Natural Resources and Geography, Bangor University. A high molecular weight substrate was added as a carbon source to the samples and the rate of 14C-substrate mineralization measured. All the work was carried out by trained members of staff from Bangor University and the Centre for Ecology & Hydrology. The measurements were taken to improve understanding of the relationship between microbial activity and soil properties and depth of sampling, under differing nutrient availability. The data were collected for the NERC project 'The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea' (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/4a8fedf4-a572-4d95-ac41-087974169af1

These data are chemical and physical data of stream water and their evolution over incubation experiments conducted on water samples taken from three headwater streams from the Conwy catchment in North Wales. Incubations involved different treatments, controlled light exposure, sterilization, and nutrient enrichment (nitrogen and phosphorus). The measured parameters are concentrations of organic carbon, total nitrogen, and major anions and cations and parameters such as pH, electrical conductivity, and absorbance. Samples were collected on two occasions for each stream between May 2014 and September 2014. Five litres of water sample were collected on the field and brought back to the laboratory for six-day incubations. Incubation started immediately after sampling. Incubation experiments were conducted in the Centre for Ecology & Hydrology laboratory, Bangor, United Kingdom. Incubations were carried out in a Bangor University laboratory using an experimental set-up built for allowing the control of light exposure. Analyses were performed in the Centre for Ecology & Hydrology (CEH) laboratory. The different treatments involved samples being kept in the dark or exposed to controlled light; additionally between 6 to 12 light-exposed samples were poisoned with Mercury(II) chloride (HgCl2) or enriched with nutrients (Nitrogen as nitrate, Phosphorus as phosphate or both). The data were collected to understand the fate of dissolved organic carbon in headwater streams depending on its sources, nature and on the inorganic nutrients availability in the headwater streams. When there was a doubt on the values, the analysis was redone, all values in the database have been validated. The sampling, incubations and analyses where performed by Ophelie Fovet, L'Institut National de la Recherche Agronomique (INRA) Rennes, L'Unité mixte de Recherche Sol Agro et hydrosystèmes Spatialisation (UMR SAS), France and co-ordinated by Chris Evans, CEH Bangor, Wales, UK. Full details about this dataset can be found at https://doi.org/10.5285/eeffacad-1f23-456a-aac0-1bda40958f75