Soil Carbon Storage and Sequestration on Pianosa Island

The soils of Pianosa, substantially homogeneous with regard to their parent material and pedological evolution, have different agronomic histories. However, the effects of agricultural activities on soil and vegetation are still very recognizable, even if there has been no human activity for seven years. Representative areas characterized by different land use were selected to give an overview of the soil of the mains ecosystems. Soil ecosystems were characterized on the basis of their chemical, physical and biological properties. The total organic and inorganic C content of the island soils was calculated and a map of distribution of soil organic carbon was drawn up. This was done in order to obtain a basis for the assessment of the dynamics of organic C as influenced by human activities, and the relationships between ecosystems and C sequestration. Physical and chemical analysis showed the impact of human activity on soil fertility. Modifications of soil structure were observed and a noteworthy reduction of soil organic C and N contents was found both in the abandoned arable areas and in the permanent pasture land compared to the macchia ecosystem, considered as the natural starting condition. However, the microbial properties showed a good biochemical recovery of the soil previously subjected to cultivation, providing interesting information both on CO2 exchanges and on resilience of the island soil ecosystems.