AbstractsEarth & Environmental Science

Quantification of topsoil organic carbon in Europe : a statistical approach combining harmonised soil and land cover point data with spatial layers

by Delphine de Brogniez

Institution: Université Catholique de Louvain
Department: Earth and Life Institute
Year: 2015
Keywords: Soil organic carbon; Europe; Spatial analysis; Monitoring
Record ID: 1076036
Full text PDF: http://hdl.handle.net/2078.1/158816


Soil organic carbon (OC) has been recognised as important for soil quality, soil resilience to degradation processes, but also as playing a major role in providing ecosystem services and in mitigating climate change. In this context, there is an urgent need for up-to-date data on the status of soil organic carbon. From local to global scale, the comprehensive assessment of soil OC faces several challenges related to soil OC spatial and temporal variability, to the lack of standard soil sampling and analytical protocols and to the absence of geo-referencing of most legacy data. The aim of this thesis was to produce the most up-to-date representation of the spatial distribution of topsoil OC content for 25 Member States of the European Union and to estimate the total amount of OC in the upper layer of the soils (0-20cm) in these same countries. To do so, ca. 20,000 OC measurements and land cover observations from the first harmonised topsoil database at European scale, the so-called LUCAS survey, were used. Specifically in this thesis, (i) a spatial database was built, consisting of soil data and environmental covariates relevant to the study of OC levels in European soils; (ii) the spatial distribution of topsoil OC content was predicted and represented by applying two different digital soil mapping techniques. The uncertainties associated to the predictions were also produced; (iii) a method for the quantification of topsoil OC stocks in Europe was proposed and applied. The results confirmed the difficulty to map and account for OC levels in soils, due to its high spatial variability and the detection of organic soils was highlighted as a major limitation in the European context. Finally, recommendations are given for a future European soil survey. (SC - Sciences)  – UCL, 2015