iSOIL - Interactions between soil related sciences -
Linking geophysics, soil science and digital soil mapping

Potential Impact

Soil is one of the world’s most valuable commodities but human activities cause several threats to its health, including erosion, floods, local/diffuse contamination, sealing and compaction. Soil degradation is already a serious problem in Europe. Until now, only nine EU Member States have specific legislation on soil protection and therefore, the European Commission prepared the Thematic Strategy for Soil Protection which is still in its infancy. It is clear that high resolution maps are required to aid the preservation of soil functions and to restore degraded soils.

From these maps soil functions can be derived, contributing to sustainable land use, water and environmental management. Providing a methodology for target-orientated soil mapping across different scales, the iSOIL project has wide-ranging applications and is suitable up to landscape scales. iSOIL is pioneering an approach whereby it unites digital soil mapping and geophysical measurements to map parameters to derive soil property maps. For that reason high resolution, non-destructive geophysical methods, mapping and modeling methods associated with Digital Soil Mapping with key soil scientific and geostatistical methods were combined to find site-specific and regional matches between soil properties and measured soil quantities.

To develop, validate and evaluate necessary concepts and strategies for the transfer of measured physical parameter distribution into maps, iSOIL is applying the notion of mobile measuring platforms by integrating different techniques, such as electromagnetic induction (EMI) methods, ground penetration radar (GPR) and gamma-ray spectrometry. Thanks to the work achieved within the iSOIL project, some existing geophysical sensing technologies, their validation, exportation, and related data processing tools (for improved measurement precision during application in soil mapping) have been improved. So as to employ this sensor-fusion approach at the geophysical platforms, the performance of these sensors was identified when used either separately or simultaneously. For that purpose, validation experiments were carried out e.g. for EMI methods and Gamma spectroscopy, leading to the recognition of advantages and disadvantages in their application at geophysical platforms and for soil mapping. Therefore, we initiated a CEN Workshop to establish a widely accepted voluntary standard for the electromagnetic induction measurement method (EMI). Some results of our validation experiments were included in discussions within the CEN Workshop and are included in the CEN Workshop Agreement (CWA 16373). This CWA is a first step in making geophysical data comparable and improving data integration.

A Field PC system for precise repositioning of measurements with an interface to GIS-map (allowing soil sampling based on area definition by GNSS coordinates) was developed, with precise repositioning allowing rapid and accurate location of measuring points and increased measurement precision. This development has a great market potential and ANS will promote this as an additional tool that can be purchased by end-users, offering better measurement repositioning.

The project also focused on emerging techniques that could be implemented into soil mapping. These techniques include acoustics/seismic waves, visible and near infrared spectroscopy (VNIRS) and spectrally induced polarization. We showed the potential and restrictions of these techniques for soil mapping using mobile platforms.

The use of geophysical data can be extremely useful in mapping soil properties but there is also a need to establish sound physical relationships between geophysical parameters and soil properties. In WP3, novel Geophysical Pedo-Transfer Functions (GPTFs) were developed linking DC and dielectric behaviour of the same medium, under variably saturated conditions. During our experiments, we recognized that the newly developed Geophysical Pedo-Transfer Functions are site-specific. Further research is required to make other assumptions for finding possible general Geophysical Pedo-Transfer Functions.

The cost factor always plays an important role during measuring campaigns. With the help of pedometrics, we followed a hierarchical approach for data collection, validation and implementation. WP4 developed and applied sampling designs for test sites, transects and validation sites to collect the required data for generating soil properties, as well as ensuring cost efficiency. Additionally, to provide valid, high resolution and transferable results sensor combinations were analyzed to derive soil properties. To map large areas, landscape segmentation was carried out, dividing areas into smaller, more homogeneous sections. This was an important step in reducing the investigated area where geophysical sensors will be applied for intensive measurements. Together, sampling, sensing, and mapping (across scales) provides operational and economic feasibility, improves resolution, speed and validity of (digital) soil mapping, and all soil-relevant planning and decision processes.

iSOIL showed that the hierarchical approach is an efficient tool for soil mapping large areas by combining geophysics, soil science and digital soil mapping tools and using all data available. The added value for the European Commission resides amongst other aspects of the project that are currently in progress for the provision of soil maps for promoting the protection and sustainable use of soil to prevent further soil degradation and to preserve soil functions. Thus iSOIL contributes directly to the implementation of the Thematic Strategy for Soil Protection. iSOIL has generated a wealth of data and this iSOIL data was uploaded and integrated into European Soil Data Centre (ESDAC). This data can be downloaded for free and used under the conditions set out in the license agreement by others.

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Important Information

Project ended in November 2011

CWA 16373 "Best Practice Approach for electromagnetic induction measurements of the near surface" is published and available at CEN or DIN Berlin

iSOIL data are available at

iSOIL is a member of the SOIL TECHNOLOGY CLUSTER of Research Projects funded by the EC

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