Anisotropie der gesättigten Wasserleitfähigkeit in Böden der Hauptnaturräume Schleswig-Holsteins (Norddeutschland) unter Acker- und Grünlandnutzung

Currently discussed phenomena like more frequent surface runoff after heavy rainfall events, increasing soil erosion and reduced yield stability can be explained to some extent by soil structure properties and a resulting, spatially differing saturated hydraulic conductivity of the soil. For this purpose, samples from 766 soil profiles under arable and grassland use in the four major natural environments of Schleswig-Holstein (Weichselian glacial area, Higher and Lower Geest, Marshland) were taken and, inter alia, the saturated hydraulic conductivity in vertical and horizontal direction and thereby its directional dependency (anisotropy) was evaluated down to the 60 cm depth. The results prove an enhanced anisotropy of the hydraulic conductivity in horizontal direction, with variations depending on the parent material, soil type and clay content, as well as the land use. The subsoils under arable land exhibit a horizontal anisotropy that is most distinct below the plow pan (≤ 40 cm depth) and can be explained by the development of a platy soil structure as a consequence of the management (tillage). Soils under grassland use exhibit a horizontal anisotropy mainly in the topsoils, whereby it is additionally very pronounced in the subsoils of the two Geest regions with a high percentage of dairy farming. Such anisotropy effects, especially in the subsoils under arable land use, can be determined soil type specifically for the representative soils of the Weichselian glacial area: Anthrosols (“Colluvic”), Stagnic Luvisols and Stagnosols. The chronological sequence of the horizontal hydraulic conductivity mirrors their high sensitivity against anthropogenic soil structure changes (development of plates), which have clearly increased in the Weichselian glacial area during the latest 30 years.