Single time point sampling of site characteristics, soil parameters and soil greenhouse gas emissions for extensive and intensive sheep-farming sites in North Wales and Devon, 2016

Intensive site. In order to sample the fields rapidly, minimising time differences between sampling points, sampling was conducted by teams of trained researchers (Extensive site, a team of five, sampling 22-24 points each; Intensive site, a team of four, sampling 24-25 points each) following pre-planned sampling routes and standardised sampling protocols. At the Extensive site, the team started by walking their individual assigned routes and placing chamber lids and gas sample vials next to each chamber. Upon all returning to their starting sample points, greenhouse gas sampling commenced (taking place between the hours of 10:40 am and 12:40 pm). Chamber headspaces were mixed by three syringe pumps prior to withdrawing a sample (25 ml) at 0 min and 60 min after chamber lid closure. Samples were injected into pre-evacuated 20 ml glass vials. Vials were over-pressurised as a quality control measure, to ensure sample vials had held their seal, (i.e. vials were returned to atmospheric pressure prior to analysis by inserting a syringe and needle, if the syringe plunger pushed back 5 ml it indicated that the vial had held its seal). At the Intensive site, samples (20 – 22 ml) were withdrawn from the chambers 40 min after lid closure and injected into pre-evacuated 20 ml glass vials. Chamber baseline (0 min) concentrations were approximated by background measurements (n=10, five before chamber sampling and five after) taken by manually sampling the atmosphere 1 m above the ground around the field. Bulk density cores (100 cm3, 0-5 cm at the Extensive site; 0-10 cm at the Intensive site) and soil samples (four 0-5 cm cores (bulked) at the Extensive site; six 2.5 cm-diameter, 0-10 cm cores (bulked) at the Intensive site) were taken from within the chamber areas. Bulk density cores and soil samples were stored in polythene bags in refrigerators (at 4 deg C) prior to analysis. Extensive site soil extractions and pH measurements were conducted within 24 h of sample collection, while analyses for Intensive site samples were completed within five days.

The Extensive site was not flown as part of the project as 1m LIDAR data were created by the Environment Agency Geomatics group and available under the Open Government Licence from Natural Resources Wales (https://datamap.gov.wales/) . The data therefore contains Natural Resources Wales information, © Natural Resources Wales and database right, all rights reserved (Licence: http://nationalarchives.gov.uk/doc/open-government-licence/version/2/). At the Intensive site, the 1 m LiDAR grid was created by the Tellus South West project (https://catalogue.ceh.ac.uk/documents/b81071f2-85b3-4e31-8506-cabe899f989a). Readers are directed to the supporting documentation for further analytical details and quality control procedures for the measurements undertaken.

This dataset is included in the following collections

Nitrous oxide emissions from livestock urine in upland grasslands in North Wales, UK