Méthodologie de constitution d'une collection d'échantillons de sols en relation avec les principaux matériaux parentaux en Wallonie (Belgique méridionale)

Abstract

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A methodology for site selection and soil sampling in relation with main parent materials in Wallonia (Southern Belgium). Despite the small size of its territory, Wallonia shows a geological context singularly varied and contrasted. From main geostructures to lithostratigraphical formations, this diversity has greatly influenced soil types. Rock weathering represents one of the main processes in soil forming. Throughout its nature and its composition, the parent material is identified as one of the main factor influencing pedogenesis and soil properties. Understanding the spatial determinism of these properties requires a better characterisation of the parent materials as well as of their spatial distribution. The Soil Science Unit of Gembloux Agro-Bio Tech has therefore initiated the collect of topsoil and subsoil samples representative of the diversity of Walloon agricultural soils, in relation with their parent materials and presenting a wide range of physico-chemical properties. The sampling strategy relies on the stratification of the territory in physical units and on the identification of the dominant parent materials and soils. The 1:20,000 Numerical Soil Map of Wallonia, the 1:250,000 Map of the Main Soil Types of Wallonia and the Map of Rural Space Units helped largely to fulfill these tasks. The very wide panel of feasible analyses on these samples opens interesting prospects on valorization of the data in a regional soil information system. Indeed, considering the importance of samples representativity in the approach, the pedotheque and analytical database should become reference tools in Wallonia, serving needs of numerous research projects.

Keywords

• Soil map
• soil parent materials
• sampling
• Belgium
• Wallonia