Topsoil and Subsoil

pH Value of Soils

SOP: 2010

UKAS accredited; MCERTS accredited

Measurement of the pH of a 2:1 water extract of a dried and ground soil sample using a pH meter.

Electrical Conductivity of Soils

SOP: 2020

Measurement of the electrical conductivity of a 2:1 water extract using a conductivity meter.

Moisture and Stone Content of Soils

SOP: 2030

MCERTS requirement

Determination of moisture and stone content of soil as percentages of its dry mass obtained after drying at <37°C.

Extractable Cations in Soils

SOP: 2400

Cations: potassium, magnesium, calcium, sodium

Soil extracts are prepared by extracting dried and ground soil samples with ammonium nitrate solution. Cations are determined by inductively coupled plasma – mass spectrometry (ICP-MS).

Extractable Phosphate in Soils

SOP: 2420

Soil extracts are prepared by extracting dried and ground soil samples with sodium hydrogen carbonate solution. Phosphate is determined by ‘Aquakem 600’ discrete analyser using ammonium molybdate.