The data consists of raw data on measured carbon dioxide (CO2) and nitrous oxide concentration (N2O) concentrations from intact soil topsoil (0-15 cm) and subsoil cores (85-100 cm) to added carbon, nitrogen and phosphorus. Four land uses (Bog, acid grassland, improved grassland and arable field) in North Wales were selected for this study with three replicates each. Intact soil cores were taken in January and February in 2014. The data consists of three datasets. The first dataset contains the measured CO2 concentration that was measured from intact topsoil cores (0-15 cm) as a result of carbon, nitrogen and phosphorus additions form a pilot study. For the pilot study intact topsoil cores were taken in November and December in 2013 from three sites. a Podzol, a coniferous forest soil and a grassland soil. These sites were not in the Conwy Catchment. The pilot study results were used to inform the experimental setup for the main experiment. The data from the main experiment, measured carbon dioxide (CO2) and nitrous oxide concentration (N2O), are reported in the second dataset for intact topsoil and subsoil cores. The third dataset contains nitrogen mineralization data from the intact soil cores that were used as control cores and did not receive any carbon or nutrient additions. The dataset contains measurements on soil nitrate, ammonium and total nitrogen mineralization rates in milligrammes of nitrogen per gramme of dry weight or per gramme of organic matter content. In both the experimental datasets, the weight of the soil cores at field capacity (in grammes) was reported and weight loss was adjusted by adding an artificial rain water solution. The incubation time (in minutes), the measured CO2 and N2O concentrations (in part per million = ppm) were recorded at the beginning and the end of the incubation. Total soil dry weight per soil core (in grammes) and the total weight of soil organic matter (loss on ignition, in grammes) are reported. The data were collected to calculate production of Measurements were undertaken by staff from the Centre for Ecology & Hydrology. The data were collected to link plant and soil nutrients to aboveground and belowground ecosystem processes to incorporate relevant parameters into the Joint UK Land Environment Simulator (JULES) model. 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/10.5285/0c17a041-8852-4800-9c04-2ab2dd858837

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 (NE/J011991/1). The project is also referred to as Turf2Surf. Full details about this dataset can be found at https://doi.org/10.5285/32392c33-8cbe-434a-a582-ab8425a5062c

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

Fifteen minute river stage height for 6 river monitoring stations within the Conwy catchment, North Wales are presented for the period 2013 to 2016. At one site (Cwm Llanerch) site the water temperature was also sampled. At all sites, the mean water height in millimetres (mm) is measured using a pressure transducer installed at an arbitrary level and recorded onto data loggers every 15 minutes. The data were collected to estimate flow in the 6 rivers. The data was collected by CEH staff members for the NERC project "The Multi-Scale Response of Water quality, Biodiversity and C Sequestration to Coupled Macronutrient Cycling from Source to Sea" (NE/J011991/1). Note: there are gaps in this data set due to equipment/battery or system failures. Full details about this dataset can be found at https://doi.org/10.5285/79de7b6e-93c2-45d3-b11d-de156dc4fefc

The data consist of general physical, biological and chemical parameters for soil samples taken in the Conwy catchment in North West Wales. Samples were collected between 2013 and 2014 across a land use intensification gradient ranging from semi-natural peatlands, acid grasslands to improved grasslands and arable fields. Soil cores were taken to a depth of 1 metre and divided into 15 centimetre (cm) depth increments. General soil physical and chemical parameters were measured at each depth increment for most of the sites. Biological (root and fine root biomass) parameters were assessed in the topsoil 0-15 cm in 5 cm intervals. 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. 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/10.5285/6566a706-9c55-4f7f-b33d-27bc29c73274

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

Data are presented of tensiometer measurements as centimetres of water from a field experiment in the Conwy catchment. The data were collected between October 2013 and January 2015 using tensiometers inserted into boreholes. The data were collected by trained members of staff from Bangor University and the Centre for Ecology & Hydrology. The samples were taken to provide supporting information for assessing the relationship between soil microbial populations and soil moisture status. 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/10.5285/875ca233-ffaa-45c2-b4d2-db7d21bc0e61

The data consists of, standing aboveground biomass, and belowground biomass measurements, from sites in the Conwy catchment. Standing aboveground biomass was measured at 7 sites and belowground biomass measurements were made at 8 sites. Data were collected in 2013 and 2014. 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. Standing aboveground biomass (grams of dry mass per metre square) in habitats dominated by herbaceous biomass was measured on 1x1 metre quadrats in four plots per site. Standing aboveground biomass in woodlands was measured in two 200 square metre areas by means of stem cores and litter collections. Belowground total root biomass (grams of dry mass per square metre) was assessed for the topsoil 0-15 centimetres in three plots per site. Measurements were undertaken by trained members of staff from Bangor University and the Centre for Ecology & Hydrology. 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/10.5285/46bb0117-ed5d-4167-a375-d84d1237cf21

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