The French Soil Quality Monitoring Network (RMQS) is a national program for the assessment and long-term monitoring of the quality of French soils. This network is based on the monitoring of 2240 sites representative of French soils and their land use. These sites are spread over the whole French territory (metropolitan and overseas) along a systematic square grid of 16 km x 16 km cells. The network covers a broad spectrum of climatic, soil and land-use conditions (croplands, permanent grasslands, woodlands, orchards and vineyards, natural or scarcely anthropogenic land and urban parkland). The physical, chemical and biological properties of the soil are measured on each site, during the first campaign and presently on the second campaign. The spatial and temporal variability of soil properties are explained by biophysical variables, sources of contamination, history of land-use and management practices on each plot. The first sampling campaign in metropolitan France took place from 2000 to 2009. This campaign focused on soil contamination assessment and made it possible to map key soil parameters (28 variables) as well as 12 trace metal elements and 70 persistent organic pollutants. The second on-going campaign started in 2016 and should last 12 years.

The sampling plot includes a sampling area and a pit at a distance of 5 m.

This dataset includes physical data from plots set from the beginning of the second RMQS campaign. Data come from measurements on dedicated samples from the pit. These measurements are made at Conservatoire Européen des Sols INRAE site d’Orléans. They are : mass of the sample at field, mass of the sample after 105°C drying, mass of coarse fragments after washing and sieving. Volumes are measured at field, according to different methods adapted to field constraints (cylinder method or excavation method). These measurements allow to calculate bulk density, soil moisture and coarse fragment content for each sample. Composite samples were collected with an auger at two sampling layers: 0-30 cm or cultivated layer named “upper layer” or “layer 1”, and 30-50 cm named “subsoil layer” or “layer 2”. Each composite sample was made up of 25 individual sample cores taken on the sampling area of 400 m², using an unaligned systematic sampling design. In some cases, a third layer was made up of holorganic layers in forests or meadows, corresponding to pedological horizons OF and OH, when these layers were sufficiently thick, (at least 1 cm) and continuous over the sampling area. This composite sample was used also as a volumetric sample. Samples were distributed along the soil profile to match each composite layer thickness and according to three pseudo-replicates by layer, in general case.

The sampling method, measurements and observations on each site are described in the “RMQS guidelines” (reference below).