Impact of ski pistes on soil properties: a case study from a mountainous area in the Mediterranean region

In this study, soils on 17 ski pistes in the Sierra Nevada, Spain, were investigated to identify changes induced by ski management practices and also to determine the effectiveness of grass seeding in restoring soil quality. When compared with unaffected reference soils, those of ski runs had substantial loss of organic carbon (?34%, ?11.9 ± 3.6 t ha^?1) and micropore volume and size (?33%, ?0.07 ± 0.01 cm³ cm^?3 and ?48%, ?1.62 ± 0.28 μm). Microstructure showed a dramatic reduction in organic cements and fungal hyphae. The organic content of soil seeded with grass significantly improved compared with soil not seeded or seeded unsuccessfully (P < 0.05), especially where the topsoil was reinstated. Organic C content, microporosity and soil respiration increased by 200% (+21 ± 5 t ha^?1), 70% (+0.07 ± 0.03 cm³ cm^?3) and 140% (+0.10 ± 0.04 mg CO₂ g^?1 day^?1), respectively. Average micropore size in aggregates which in undisturbed soils was 3.40 ± 0.28 μm reverted to 3.52 ± 0.36 μm. However, the microstructure of the revegetated soils did not attain the levels of organic cements and fungal hyphae in the natural soils. Dolomite and salts were added to the soil to aid slope stabilization, fertility and de‐icing of access tracks. As a consequence, there were increases in pH, exchangeable sodium percentage (ESP), electrical conductivity, calcium carbonate equivalent and base saturation. The influence of management on soil properties was found to be greater than that of environmental factors.