Unsuitable land use worldwide has led to environmental degradation. Land use effects on the environmental component of soil quality were assessed in 47 benchmark soils of three natural environments (Xerolls, Xerepts, and Cryepts) in southern Spain. Within each environment, soil groups with traditional land uses were compared with native sites. Soil quality changes were inferred by measuring the relative changes in chemical and physical soil properties. Irrigated terraces, rainfed cropland, and grassland, all within Xerepts, and grazed thyme scrub land were degraded with respect to native sites (significant differences at P < 0.05). In all cases, total porosity, macroporosity, and cation exchange capacity declined by more than 18% (-0.11 cm(3) cm(-3)), 30% (-0.11 cm(3) cm(-3)), and 48% [-10.5 cmol(+) kg(-1)], respectively. Except in irrigated terraces, soil erodibility increased by as much as 59% (+0.16 USLE factor). Substantial losses of soil organic C (37%, -14.7 Mg ha(-1)), available water (52%, -36.2 mm), total N (65%. -1.7 Mg ha(-1)), and rooting depth (68%, -39 cm) were also observed in grassland and thyme scrub land. These changes suggest adverse effects on environmental protection functions of soil because of soil compaction and/or elimination of structural binding agents. Scanning electron microscopy images confirmed these morphological changes in microaggregates. Similar changes did not occur in cropland and grassland within Cryepts or in planted pine forest land. Reforestation with pine (Pinus nigra Arnold, Pinus sylvestris L., and Pinus uncinata Mill. ex Mirb.) provided organic cements and fungal hyphae that reinforce soil aggregation as well as ecologically valuable humus. Because cropland and grassland were able to recover the natural soil properties without human activity, we deduce that Cryepts are resilient.
planted pine forest, referred to as 'pine reforestation'. The pinewoods are plantations of p. nigra, p. sylvestris, and p. uncinata more than 40 years old. No additional detail provided.
|Climate change impacts||Effect of Nbs on CCI||Effect measures|
|Reduced soil quality||Positive||“Twelve common quantitative soil characteristics directly related to the ecological functions of environmental protection of the soil were used as indicators to infer soil quality” (e.g. rooting depth, pH, porosity, bulk density etc.) + quality of the soil organic matter (humus characteristics) and the structure (SEM fabrics)|
Sierra Nevada Mountains National Park in southern Spain.