Soil type and land use effects on tensorial properties of saturated hydraulic conductivity in northern Germany

• Published in: European journal of soil science Vol. 71; no. 2; pp. 179 - 189
• Main Authors: Horn, Rainer, Mordhorst, Anneka, Fleige, Heiner, Zimmermann, Iris, Burbaum, Bernd, Filipinski, Marek, Cordsen, Eckhard
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2020; Wiley Subscription Services, Inc
• Subjects: Alluvial deposits; Alluvium; Anisotropy; Arable land; arable soil; Bioturbation; Clay; clay content; Clay soils; Dairy farming; Dairy farms; Direction; Geology; Grain size; Grain size distribution; grassland; Grasslands; Harvesting; horizontal anisotropy; Horizontal orientation; Hydraulic conductivity; Hydraulics; Land use; Marshes; Marshlands; Outwash; Profiles; Regions; Sedimentation; Size distribution; Slurries; Soil; Soil analysis; soil compaction; Soil horizons; Soil management; Soil profiles; Soil properties; Soil structure; Soil types; Soils; Subsoils; tillage systems; Topsoil; Trampling; Germany
• ISSN: 1351-0754; 1365-2389
• DOI: 10.1111/ejss.12864

Long‐term soil management can produce anisotropic impacts on soil structure, resulting in differences in horizontal and vertical hydraulic conductivity. As limited data exist on these impacts, this study provides a broad‐scale assessment across 764 soil profiles under arable and grassland use in northern Germany (Federal State: Schleswig‐Holstein). The soils were sampled in the four geological regions: Weichselian glacial region, the sandy outwash region (Lower “Geest”), the Saalian glacial region (Higher “Geest”) and the marshland with alluvial deposits. Saturated hydraulic conductivity (Ks, either in a horizontal (Ks_h) or vertical direction (Ks_v)) and the pore‐size distribution were determined on undisturbed soil samples (100 cm3), whereas the grain size distribution was analysed on disturbed samples from the major soil horizons. This research work presents Ks_h and Ks_v values for representative soil types of the four geological regions down to a depth of 60 cm. Irrespective of the parent material in the four geological regions, arable soils showed a pronounced anisotropy of Ks in the horizontal direction. However, Ks_h and Ks_v also showed a high variability across the geological regions from approximately 1 to 800 cm d−1, whereas the ratio of Ks_h to Ks_v ranged from 0.1 to 500. In the marshland (dominated by Gleysols), the direction‐dependent values were superimposed by sedimentation processes of the marine material and/or structural development processes such as vertical shrinkage or bioturbation processes. Under grassland, the topsoils primarily indicated horizontally anisotropic flow conditions. In the “Geest” area with a high share of dairy farming, both top‐ and subsoils displayed the highest horizontal anisotropy values, indicating the stress‐induced formation of a platy structure caused by trampling, grass harvesting or slurry application with heavy machinery. Soil type (e.g., Stagnic Luvisols, Stagnosols or Anthrosols) and horizon‐dependent horizontal anisotropy were also more pronounced in arable than in grassland subsoils. Highlights Hydraulic conductivity in arable subsoils shows mostly horizontal behaviour. Hydraulic conductivity in grassland topsoils shows mostly horizontal behaviour. The anisotropic degree and its direction depend on land use type and clay content of the soils.