The study investigates the spatial variability of the cone index (CI) and its implications for vehicle mobility across two contrasting regions in Poland: the Suwalki Gap and Garwolin County. Background motivation stems from the need to assess off-road trafficability for agricultural, forestry, and other vehicles operating on soils whose strength varies seasonally and spatially. Using 230 penetrometric measurements collected with an electronic Penetrologger equipped with a soil moisture sensor, CI values were recorded to a depth of 80 cm and supported with soil–agricultural maps and Sentinel-2 land-cover data. Results demonstrate clear relationships between CI, soil moisture, land cover, soil type, and depth. Wetlands exhibited consistently low CI (<1 MPa), while agricultural, artificial, and forested areas showed increasing resistance with depth, surpassing 2 MPa in deeper layers. Seasonal differences were pronounced: summer drying increased surface CI, whereas autumn profiles were generally softer but more uniform. Regression analysis confirmed a strong negative correlation between soil moisture and CI, particularly below 20 cm. Comparative assessment with vehicle cone index thresholds indicates that most terrains are suitable for heavy vehicles, except saturated wetlands, which pose significant trafficability constraints. The findings emphasize the importance of depth-specific CI assessment, the strong influence of local soil disturbances, and the need for high-density measurements to support real-time mobility modelling for agricultural and crisis-management applications.
Pokonieczny et al. (Thu,) studied this question.