Provenance & quality
Soil samples were collected in 2007 by Countryside Survey field surveyors, who were provided with a field sampling manual and underwent training for sample collection and processing. Protocols were also provided to cover all aspects of processing of the soil cores from logging in of cores as they arrived at the laboratory to basic measurements, chemical analysis and archiving the final samples. Soils were sieved to 2 mm and air-dried before storage.
Each soil sample was scanned twice to obtain repeat spectra, with the sample cup being rotated 180 degrees between scans, and the average of these two spectra included in the dataset. Each individual spectrum (i.e. both from the paired scans) was visually inspected and those containing scanning errors were discarded.
All MIR analyses were conducted at the Organic Geochemistry Facility, BGS (contact email@example.com for details).