Organic carbon storage capacity in different soil types of Girona Province under forest, pasture and rapeseed cultivation: implications for carbon sequestration

ENG- The soil is the upper part of the Earth’s crust that irrespective to its little depth allows the organisms life, is a water reserve and nutrients source for plants, owns high buffer capacity but it is not a short-term renewable resource, hence it must be protected and preserved. The soil is a living organism functioning as a substrate for agricultural activity to secure grocery supply and a natural body delivering ecosystems services to communities. One of the main soil components is the soil organic carbon (SOC), directly influencing most of the physical, biological, chemical and biochemical soil properties. During the last decades an intensification of the research activity on the soil carbon dynamics has occurred because of the decrease of the SOC stocks in soils due to land use, land use change and land abandonment. In this context the objective of this thesis was to evaluate the main soil properties and specially the soil organic carbon storage potential in three different soil types in the Girona province located at Fornells (Calcixerept formed on calcareous materials), Canet d’Adri (Haploxerand formet on Basanite) and Brunyola (Xeropsamment formed on granodiorite) and similar soil use: under forest, pasture and rapeseed cultivation. Physical soil properties at surface such as temperature (T), moisture (M), shear strength (SS), mechanic impedance (MI), infiltration rate (IR), and hydraulic conductivity (HC) were monitored along 2020, 2021 and 2022 and showed significant variability among soils and uses. In particular SS and MI resulted much higher in soils under pasture and Fornells soil showed the highest values according to overgrazing. Likewise, cultivated soils showed high values of SS, IR and HC indicating that these soils may modify surface properties due to field works favouring water entry after ploughing or make it difficult for surface sealing during draught periods