Long-term effect of pre-industrial biochar on aggregate stability and interrill erodibility of agricultural soils with different textures in Wallonia (Belgium)

Details

Supervisors

Bielders, Charles ; Zanutel, Martin

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences et technologies de l'environnement

Abstract

Water erosion causes among others the loss of fertile soil, eutrophication of water bodies or floods. Different techniques to limit water erosion already exist. This master’s thesis studies the efficiency of one of them: the application of biochar to the soil. Biochar is a carbonaceous component produced by the oxydation of biomass in absence of oxygen and used as soil amendment. Biochar is believed in the short-term to improve soil fertility by increasing nutrient and water retention, soil porosity and aeration, microbial activity, etc. Its impact depends on the texture of the soil on which it is applied. Due to its high resistance to decomposition, biochar remains in soils for several hundreds of years. Therefore its efficiency in the long-term must be studied. Three agricultural plots with a different texture (silty-loam, loam and sandylaom) were selected containing fauld areas (150 years old charcoal). The susceptibility of the soil to water erosion was studied through two parameters: aggregate stability (protocol Le Bissonnais (1996)) and soil erodibility (simulated rainfall). Results indicate that biochar does not significantly increase aggregate stability. However, biochar did significantly increase the permeability and reduced the sediment flux of the surface seal formed during the first simulation. This effect disappeared during the second simulation 24h later. Finally, pre-industrial biochar had no significant influence on the interrill erodibility of the soil.