Translating the Dutch national soil map to the international WRB (World Reference Base) classification.The Dutch soil map is the most valuable source of nationwide high resolution soil information of the Netherlands. The map is classified using the Dutch classification system, which is specifically designed for Dutch soils and landscapes. This information is difficult to use for international soil communities and translating the map goes beyond linguistic translations or mapping a map unit to an international class. We created a translation from Dutch soil classes to international soil classes (WRB) where we estimated the certainty and spread of the class translation based on ~350.000 soil profile descriptions. The translated soil map is of a much higher resolution than the existing WRB map and the information on uncertainty can help the international soil communities understand the meaning behind the classes. We believe the method used in this research could help other countries translate their classification systems to, for example, WRB and help to harmonize fragmented soil data to create a better European soil map.

Sustainable soil management is recognised as a pivotal solution for addressing current and future global challenges, but existing global and national soil property maps often lack the fine-scale resolution required for local or intra-field assessments. Here, we aimed to develop an open access framework to downscale soil property maps using remote and proximal sensor data and test it for predicting soil organic carbon (SOC) and clay across different regions of Europe. To facilitate the dissemination of this framework, we developed the R package "soilscaler", which contains integrated functions for producing downscaled soil maps. This approach uses coarse resolution maps as a baseline, incorporating sensor data and soil observations to train a model explaining local variation of soil properties. We tested the framework in Denmark, Northern Ireland, Lithuania, The Netherlands, and Turkey. For comparison, we also created high-resolution maps using a conventional digital soil mapping (DSM) approach for each field independently. We found that the downscaling performance depends on the quality of the coarse-resolution soil maps, the spatial variability of soil properties within a given field, and the range of inter-field variations in each country. Although the downscaling process showed lower performance than the conventional DSM approach, the results indicate that the downscaled maps better represent local variability than existing national and global soil maps. Additionally, we found that remote sensing sensors generally better represent the spatial distribution of SOC, while proximal soil sensors better capture clay contents. Future studies should focus on gathering more sensor data and correlating it with soil properties to improve predictions based solely on sensor data.

Soil compaction and soil bulk density are key soil properties affecting soil health and soil ecosystem services like crop production, water retention and purification and carbon sequestration. The standard method for soil bulk density measurements using Kopecky rings is very labour intensive, time consuming and leaves notable damage to the field. Accurate data on bulk density are therefore scarce. To enable large-scale data collection, we tested a new portable gamma ray sensor (RhoC) for in situ field and dry bulk density measurements up to 1 m depth. In this first validation study, measurements with the RhoC-sensor were compared with classic ring sampling. Measurements were made in two agricultural fields in the Netherlands (a sandy clay loam and a sandy soil), with large variation in subsoil compaction. At 10 locations within each field, three soil density profiles were made. Each profile comprised six depth measurements (every 10 cm from 10 to 60 cm depth) using the RhoC-sensor and Kopecky rings, resulting in 30 pairwise profiles and 180 measurements in total per field. At an average soil density of 1.5 g/cm3, the relative uncertainty was 9% for the Kopecky rings and 15% for the RhoC-sensor. Because the RhoC-sensor is easy and quick to use, the higher relative uncertainty can easily be compensated for by making additional measurements per location. In conclusion, the RhoC-sensor allows a reliable quantitative in situ assessment of both field and dry bulk density. This provides the much-needed possibility for rapid and accurate assessment of soil compaction. The acquisition of this data supports the calculation of soil organic carbon stocks and is indispensable for (national) soil monitoring, to assess soil health and to inform sustainable land management practices for sustained or improved soil health and provision of soil ecosystem services, such as requested in the proposed EU Directive on Soil Monitoring and Resilience.

Soil compaction and bulk density are key soil properties, affecting the contribution of soil health to soil services like crop production, water retention and purification, and carbon sequestration.However, the standard measurement with rings is laborintensive and expensive.To overcome classic limitations of soil density measurements we propose the use of a portable gamma sensor to measure bulk density in situ.A validation was performed in two locations, on sandy clay loam and sand soil in the Netherlands, both with large within field variation in subsoil compaction.In both fields ten soil pits were dug, where in every soil pit 3 profiles with the RhoC soil density meter were sampled.In addition, 3 profiles with undisturbed soil cores in rings were taken at every 10 cm depth, up until 60 cm depth.In total, 180 rings and 180 RhoC samples were taken per field.We will discuss the uncertainty of the RhoC method with respect to the uncertainty due to heterogeneity in the field.This novel technique allows the quantitative assessment of bulk density in the field at various depths.This measurement is essential for rapid and accurate soil compaction assessment and soil organic carbon stocks calculation.The acquisition of this data for land managers, advisors, and (national) soil monitoring is indispensable for the sustainable management of soils for the provision of ecosystem services, such as requested in the proposal EU Directive on Soil Monitoring and Resilience.

A recent assessment states that 60–70% of soils in Europe are considered degraded. Protecting such valuable resource require knowledge on soil status through monitoring systems. In Europe, different types of monitoring networks currently exist in parallel. Many EU Member states (MS) developed their own national soil information monitoring system (N-SIMS), some being in place for decades. In parallel in 2009, the European Commission extended the periodic Land Use/Land Cover Area Frame Survey (LUCAS) led by EUROSTAT to sample and analyse the main properties of topsoil in EU in order to develop a homogeneous dataset for EU.Both sources of information are needed to support European policies on soil health evaluation. However, a question remains whether the assessment obtained by using soil properties from both monitoring programs (N-SIMS and LUCAS Soil) are comparable, and what could be the limitations of using either one dataset or the other.Conducted in the context of European Joint Programme (EJP) SOIL, this study shows the results of a comparison between N-SIMS and LUCAS Soil programs among 12 different EU member states including BE, DE, DK, EE, ES, FR, DE, HU, IT, NL, PL, SE and SK. The comparison was done on: (i) the sampling strategies including site densities, land cover and soil type distribution; (ii) the statistical distribution of three soil properties (organic carbon, pH and clay content); (iii) two potential indicators of soil quality (i.e. OC/Clay ratio and pH classes). The results underlined substantial differences in soil properties statistical distributions between N-SIMS and LUCAS Soil in many member states, particularly for woodland and grassland soils, affecting the evaluation of soil health using indicators. Such differences might be explained by both the monitoring strategy and sampling or analytical protocols exposing the potential effect of data source on European and national policies. The results demonstrate the need to work towards data harmonization and in the light of the Soil Monitoring Law, to carefully design the future of soil monitoring in Europe taking into account both LUCAS Soil and N-SIMS considering the significant impact of the monitoring strategies and protocols on soil health indicators.

De Bodemkaart van Nederland, schaal 1:50.000, is onderdeel van de Basisregistratie Ondergrond (BRO), eencentrale registratie met publieke gegevens over de Nederlandse ondergrond. Wageningen Environmental Research(WENR) onderhoudt dit bestand voor het ministerie van LNV.Dit rapport presenteert verbeterde en recente informatie over de bodem, het voorkomen van veen en landvormenin de gemeente Vijfheerenlanden, die is ingewonnen bij de actualisatie van de Bodemkaart en GeomorfologischeKaart in 2022.---Update of the soil map of the municipality of Vijfheerenlanden: Remapping the spatial distribution of peat soilsThe Soil Map of the Netherlands at scale 1:50.000 is part of the Dutch National Key Registry of the Subsurface(BRO), the central registry of public data on the subsurface of the Netherlands. Wageningen EnvironmentalResearch (WENR) maintains this map for the Ministry of Agriculture, Nature and Food Quality.This report presents improved and updated information on soils, the occurrence of peat and landforms in themunicipality of Vijfheerenlanden, that was collected during the update of the Soil Map and Geomorphological Map in2022

Soil compaction and soil bulk density are gaining in importance as soil parameters. The standard measurement with rings is labour intensive and therefore expensive. Medusa Explorations developed a sensor for in situ density measurements, the RhoC. This sensor measures in situ a full soil profile of bulk density every 5 cm up to 1 m depth in 15 minutes, without the need to extract a soil core. The measurement uses gamma ray attenuation combined with a soil moisture sensor. A validation study was performed in two locations, on sandy clay loam and sand soil, both with large within field variation in subsoil compaction. The first results show a good correspondence between both methods. Statistical analysis shows a slightly lower precision for the RhoC measurements than for the rings measurements. The results of this validation study will be discussed.

The report describes what regenerative and conventional agriculture can mean in a Dutch context and shows the actual and potential benefit of regenerative agriculture compared to conventional agriculture with respect to soil carbon sequestration for a practical case study of a Dutch farm on marine clay soils in the Netherlands.

Changes in soil organic matter (SOM) content and soil organic carbon (SOC) stock in the 0-30 cm and 30-100 cm soil layers between 1998 and 2018 in the Netherlands were estimated by repeated sampling of 1152 locations in the Soil Sampling Programme (SSP). These locations were selected following a stratified simple random sampling design. We discuss various barriers we met: restricted accuracy of information on soil bulk density, uncertainties due to positional errors, differences in sampling support, and changes in laboratory analysis methods since 1998. Domains of interest such as mineral soils were defined either on the basis of the stratification of the SSP sample (geomatching) or on the basis of soil profiles observed at the selected locations (classmatching). The mean SOM content changed significantly in the 30-100 cm layer (-17.68 g kg(-1)) in the entire area of interest (non-built-up area in the Netherlands) between 1998 and 2018 (at a 5% significance level). A decrease in SOM content between 1998 and 2018 could be shown for the 0-30 cm layer in mineral soils under cropland if classmatching was applied (at a 5% significance level), but no change could be shown in this layer in the remaining domains of interest, whether geomatching or classmatching were applied. For the 30-100 cm layer in mineral soils, significant changes in mean SOM content were shown by classmatching: -8.59 g kg(-1) under cropland and -4.75 g kg(-1) under grassland. The calculations indicate that SOC stocks decreased between 1998 and 2018 in both the 0-30 cm and the 30-100 cm layer of mineral soils under both cropland and grassland. The accuracy of the bulk density data needs to be improved in future measurements to increase the accuracy of calculations of the SOC stock changes.

The Soil Map and Geomorphological Map of the Netherlands at scale 1:50,000 are the soil and landform map databases of the Netherlands. They are part of the National Key Registry of the Subsurface (BRO), the central registry of public data on the subsurface of the Netherlands. Wageningen Environmental Research (WENR) maintains these maps for the Ministry of Agriculture, Nature and Food Quality. This report presents improved and updated information on soils and landforms for parts of the Utrechtse Heuvelrug, Gelderse Vallei and Veluwe regions collected during the update and review of the Soil Map and Geomorphological Map in 2020 and 2021. Examples are given on how the maps can be used in conjunction for the planning and management of the soil-water system in the Gelderse Vallei. The examples were taken from the planning and environmental strategy of the Regional Water Authority Vallei en Veluwe (Blauwe Omgevingsvisie 2050).

Op basis van de in 2018 uitgebreid gemeten dataset (CC-NL) van meer dan duizend locaties over heel Nederland is de staat van de Nederlandse landbouwbodems weergegeven, een zogenaamde nulmeting bodemkwaliteit. Voor de bepaling van de kwaliteit van landbouwbodems in Nederland is de huidige lijst 'Bodemindicatoren voor Landbouwbodems in Nederland (BLN) leidend. Het rapport beschrijft de wetenschappelijk verantwoording van de landelijke kaartbeelden en statistische verdelingen van de gemeten indicatoren voor bodemkwaliteit. Het geeft hiermee de staat van de Nederlandse landbouwbodems in 2018 weer zonder kwaliteitsoordeel. Voor ontbrekende indicatoren is een meetplan opgesteld. De resultaten geven een goede basis voor de landsdekkende monitoring van de bodemkwaliteit in landbouwgronden met bodemkwaliteitsindicatoren.

For seven TOP areas in the province of Utrecht an analysis was made of the extent to which these areas meet standards of water table depth and groundwater quality. This so called target realisation was compared with the situation in 2013. The results of the analysis indicated that desiccation has more or less been reduced. However, it has also been shown that conditions could have been created that are too wet to meet the abiotic standards for the nature types being pursued.