ETD

• EC
• EM38
• EMI
• Management zones
• Soil Roughness

Management zones (MZs) translate within-field variability into operational units for site-specific agricultural management. Electromagnetic induction (EMI) enables rapid, non-invasive mapping of apparent soil electrical conductivity, although measurements may also be affected by transient surface conditions and sensor–soil geometry. This thesis investigated how soil surface roughness affects EMI response and management-zone delineation in a tilled arable field. EM38 surveys were conducted before and after rotary power harrowing, together with measurements of soil water content and surface roughness. Changes in transformed electrical conductivity (ECt) were assessed statistically and geostatistically, while fuzzy c-means clustering compared zones derived from ECt alone and from ECt combined with the tortuosity ratio. After tillage, mean ECt decreased by 13.1% and its spatial variability declined, although part of the original field-scale pattern was preserved. Adding roughness increased the number and fragmentation of the resulting zones. These findings indicate that roughness provides additional spatial information but may also introduce transient or acquisition-related effects. ECt-only classifications may therefore provide a more stable basis for management of zoning, whereas roughness-inclusive maps are better suited to evaluating surface effects and survey reliability.