Increased drainage effects on soil properties and water quality
Soil stores the largest terrestrial pool of organic carbon (C), and can act as a source and/or filter for water pollutants like nitrogen (N), phosphorus (P), and suspended solids (SS). Fine soil particles (clays, Fe, Al and Mn (hydr)oxides, carbonates) play a crucial role in the stability of carbon and nutrients in soil. Previous studies have found that even a few decades of increased drainage, due to subsurface drainage installation, can substantially change the proportion and composition of fine soil particles closest to the drain. This raises questions regarding increased precipitation, and thus increased soil water flux, effects on the mineral composition and C and nutrient stability in soil. By studying soils on a water flux gradient perpendicular to subsurface drainage pipes, the IDESoWa project will calculate soil element fluxes within soil, and their losses with drainage water. It will determine relationships between between drainage water chemistry and soil properties. By jointly analysing published literature, weather records, precipitation chemistry, drain flow quantity, and soil and drainage water properties, the IDESoWa project will develop a conceptual framework for soil development in two common European agricultural soils (Cambisol and Luvisol), and under two agricultural practices (tilled soil vs. pasture).