Soils in Mediterranean areas are very poor in organic matter and are exposed to progressive degradation processes. Therefore, a lot of actions are conducted to improve soil quality and hence mitigate the negative environmental and agronomic limitations of these soils.
Improved cultivation systems have been introduced in recent years increasing the contents in soil organic carbon with a view to altering that of total atmospheric carbon. Increasing soil organic carboncontent enhances soil quality, reduces soil erosion and degradation, improves surface water quality, and increases soil productivity. Important land uses and practices with the potential to sequester SOC include conversion of cropland to pastoral and forest lands, conventional tillage to conservation and no tillage, no manure use to regular addition of manure, and to soil specific fertilization rate.
Moreover, the organic waste addition to the soils is especially useful in Mediterranean regions, where the return of organic matter to soil not only helps soils store C, but also has additional, well-known benefits such improving soil structure, increasing soil fertility and preventing soil erosion. In contrast to the typically severe erosion and degradation processes occurring in Mediterranean soils, a wide range of underused OM resources such as agro-industrial wastes currently exists that might be highly useful as organic amendments to address these environmental problems.
Soil organic carbon is an important component of global carbon cycle, and the changes of its accumulation and decomposition directly affect terrestrial ecosystem carbon storage and global carbon balance. The ability of soil to store organic carbon depends to a great extent on climate and some soil properties, in addition to the cultivation system in agricultural soils. Although it is widely accepted that soil organic matter concentrates largely in the top 30 cm of soil, there is growing evidence that deeper soil horizons can sequester large amounts of soil organic carbon despite the small amounts present in the subsoil. Available knowledge on soil organic carbon distribution and control of carbon sequestration in soil profiles can be used to predict the effects of changes in land use and management on carbon emissions.
Contributions dealing with different management, uses and land use change, climatic and topographic conditions and organic waste addition that can affect to soil organic carbon storage are welcome.