EJP Soil double sampling study (Task 6.3): physicochemical soil data of 166 Belgian LUCAS 2022 sampling points

EJP Soil Double Sampling Study:  physicochemical data Flanders (Belgium)

During the elaboration of EJP Soil deliverable 6.3 of Work Package 6, entitled ‘Proposal of methodological development for the LUCAS programme in accordance with national monitoring programmes’ (Bispo et al., 2021), a large majority of partners (23) suggested to launch a double sampling study by collecting national soil samples on LUCAS points to compare LUCAS and National design strategies and sampling and analytical protocols.

For Flanders region, we conducted a double-double sampling study on 166 LUCAS points that were selected as representative for cropland, grassland and woodland soils. 

Each of these LUCAS points were sampled according to the LUCAS sampling scheme and the national (Cmon) scheme by our national surveyors (double sampling type 1) , and sampled by LUCAS surveyors (COBA group) for analysis by the LUCAS central lab so that also the laboratory results could be compared for the LUCAS 2022 campaign (double sampling type 2).    

The LUCAS 2022 campaign selected also for Belgium 11 LUCAS Biopoints: 5 in Flanders, 1 in Brussels region and 5 in Wallonia. At the EJP National HUB we agreed to sample all 11 Belgian biopoints both for physico-chemical soil properties (this study) as for soil biodiversity assessment through eDNA metabarcoding (Lambrechts et al., 2025).

The dataset comprises 3 CSV files: (1) list of sampling points with LUCAS pointID, coordinates and metadata, (2) the physico-chemical soil data of each point according to the LUCAS and Cmon sampling scheme, (3) the soil bulk density data according to the Cmon sampling scheme.

Samples were collected between 15 June 2022 and 23 May 2023.

Variables and units

Variable
Description
Unit
Method

Thickness
Layer thickness
cm

Depth
Depth of layer (negative for forest floor)
cm

Sand
Sand fraction by Laser Diffraction (LD)
vol%
ISO11277 & ISO13320

Silt
Silt fraction by LD
vol%
ISO11277 & ISO13320

Clay
Clay fraction by LD
vol%
ISO11277 & ISO13320

TC
Total carbon
g/kg
ISO 10694

TIC
Total inorganic carbon
g/kg
ISO 10694

TOC
Total organic carbon (TC-TIC)
g/kg
ISO 10694

TN
Total nitrogen
g/kg
ISO 13878

pH_KCl_v_v
pH KCl 1:5 v/v
-
ISO 10390

EC_m_v
Electric conductivity m/v
µS/cm
ISO 11265

EC_v_v
Electric conductivity v/v
µS/cm
ISO 11265

pH_H20_m_v
pH H2O 1:5 m/v
-
ISO 10390

pH_H20_v_v
pH H2O 1:5 v/v
-
ISO 10390

pH_KCl_v_v
pH KCl 1:5 v/v
-
ISO 10390

pH_CaCl2_m_v
pH CaCl2 1:5 m/v
-
ISO 10390

pH_CaCl2_v_v
pH CaCl2 1:5 v/v
-
ISO 10390

BD_mean
Bulk density mean of 4 rep
g/cm³
ISO 11272

BD_sd
Bulk density stdev of 4 rep
g/cm³

BD_CV
Bulk density CV of 4 rep
g/cm³

SWC_volp_mean
Volumetric moisture content mean of 4 rep
vol%

SWC_volp_sd
Volumetric moisture content sd of 4 rep
vol%

The data are evaluated in the report: De Vos, B. & Lambrechts, S. 2025. Comparing LUCAS and Cmon sampling schemes and survey data on 166 LUCAS 2022 points in Flanders, Belgium. EJP Soil Deliverable 6.3. Horizon 2020 EJP Soil grant agreement 862695. (to be published on Zenodo after Embargo period of 6 months).