Impact of Land Use Change and Afforestation on Soil Properties in a Mediterranean Mountain Area of Central Spain

Afforestation can improve hydrological processes, such as infiltration, in basins and, therefore, reduce the impact on human populations of floods, soil erosion, landslides, droughts, and climate variation. The aim of this work was to analyze how afforestation and other changes in land use influence infiltrability and the evolution of soils. Infiltration rates, soil water repellency, and physical and chemical properties of sandy loam soils were measured in four types of land: native holm oak forest, afforested 20-year-old pine forest, shrubs, and grasslands. Non-forest covers are the result of the degradation of native oak forests for centuries, while the pine afforestation in this study took place on a perennial wet mountain pasture (cervunalito). Our results show that soil infiltration rates are much higher in pine afforestation areas (857.67 mm·h−1) than in holm oak forest (660.67 mm·h−1), grasslands (280.00 mm·h−1), or shrubs (271.67 mm·h−1). No statistically significant differences in fertility, organic matter content, bulk density, or effective porosity were found between afforestation areas and other types of cover; however, pine afforestation improved the drainage of the soil, as its infiltration rate was higher than that of the native holm oak forest.