Soil organic matter is essential for preserving a healthy soil, maintaining fertility, managing water storage, control the soil structure, decreasing soil erosion risk and store carbon for climate change mitigation. There is a growing realization amongst policy-makers that reliable and accurate soil monitoring information about this finite, non-renewable resource is therefore mandatory as stressed by many national and international treaties and policies, e.g., the Sustainable Development Goals (SDGs), the UNCCD Land Degradation Neutrality and relevant EU policies (Common Agriculture Policy -CAP- and Green Deal).

In this frame, the overall objective of the ESA WORLDSOILSproject is to develop a global Earth Observation Soil Monitoring System utilizing information available from operational, in situ and reference databases, as well as information derived from space-based Earth observation together with blending and modelling techniques. The development shall be based on monitoring top soil organic carbon (SOC) and implemented in a modular way on a suitable cloud environment allowing its future extension to additional soil indices. The system’s grid resolution supported by appropriate covariate information shall be 100 m x 100 m globally and 50 m x 50 m over Europe, shall provide appropriate confidence metrics and shall allow assessing temporal changes of the global top soil layer at least once per year. The monitoring system integrates both, indirect predictions of SOC for permanently vegetated areas through digital soil mapping techniques and direct prediction for exposed soils including croplands through imaging spectroscopy techniques transferred to multispectral systems, supported by earth observation information and in situ soil data.

The contribution of the GFZ to the project focuses on the later part including the evaluation of state-of-the-art spectral modelling techniques for SOC prediction such as LocalPLSR for operational and reliable use, as well as the general assessment of feasibility of applying laboratory spectral models to the scale of spaceborne imagery taking into account effect of mixture and disturbing effects (e.g. soil moisture, roughness) in a realistic landscape scenarios. Furthermore, GFZ is involved in the implementation of selected algorithms, and shares responsibility for the case study design and validation of final project outcomes at various test sites.

Project website

Proposed architecture for an EO based soil monitoring system consists of different processing approaches to produce a final SOC product that can cope with terrain heterogeneity, different climate regimes and seasonality.

Publication and conference presentations

Chabrillat, S., Milewski, R., Kuester, T., Dvorakova, K. and Van Wesemael, B. (2021), Development of a Spatially Upscaled Soil Spectral Library (SUSSL) of cropland signatures for EO sensors data simulation and calibration/validation of topsoil organic carbon prediction models, General Assembly European Geosciences Union, Vienna, 19-30 April 2021 (online), EGU21-14365.