GEMAS | Soils Summary Information

Synopsis

The Geochemical Mapping of Agricultural Soils (GEMAS) is a European-wide project between the component geological surveys of the EuroGeoSurveys and Eurometaux (European Association of Metals).

The aim of the project is to produce one of the best harmonised and directly comparable datasets on soil quality and metals in soils that exists at the EU scale.

In 2008 across Europe, 2211 samples of arable soil (0-20 cm) and 2118 samples of grazing land soil (0-10 cm) were collected at an average sampling density of 1 sample per 2500 km2. The extensive analytical programme determined more than 50 elements by ICP following an aqua regia extraction and more than 40 elements determined by XRFS.

The British Geological Survey collected the UK soil samples for this project (see G-BASE). Sampling sites were based on 50 x 50 km cells with 65 sites in England, 51 in Scotland, 14 in Wales and 8 in Northern Ireland.

Samples were collected according to an agreed protocol (EGS Geochemistry Working Group, 2008) which is summarised below.

Soil sampling methodology

Soil sampling in the field

Each sample is a composite of a minimum of 5 subsamples yielding a 2-2.5 kg sample collected in a RILSAN bag. Subsamples are collected from the corners and centre of a 10 x 10m square. A stainless steel spade is used for collection.

The arable sample is taken from the ploughing layer (0-20 cm), whilst the grazed land sample is collected from the top 10 cm (removing any living surface vegetation). Samples are dried at a max of 40ºC, disaggregated as necessary and sieved to < 2 mm using a nylon screen.

Data availability

Results for the UK are freely available from the country representative on the GEMAS Project, namely Andreas Scheib (BGS). There are some restrictions for some elements (e.g. Au) and analysis is currently in progress. In January 2011, for arable and grazing soils the ICP aqua regia, pH, CEC and TOC results were available. XRFS results were additionally available for the grazing land soils.

References and links

EGS Geochemistry Working Group. 2008. EuroGeoSurveys Geochemical mapping of agricultural and grazing land soil of Europe (GEMAS) - Field manual. Report for EuroGeosurveys/Eurometaux. Report No. 2008.038. Geological Survey of Norway (NGU), 46pp. NGU, Trondheim, Norway.

Reimann, C., Demetriades, A., Eggen, O.A., Filzmoser, P. et al. 2009. The EuroGeoSurveys geochemical mapping of agricultural and grazing land soils project (GEMAS) - Evaluation of quality control results of aqua regia extraction analysis. Report No. 2009.049. Geological Survey of Norway (NGU), 94pp. NGU, Trondheim, Norway.