Soil organic matter quality under different levels of cropping systems intensification

The study on the impact of different land uses on soil organic matter (SOM) fractions have important implications for the identification of sustainable land and agricultural management practices and the possibility to develop actions finalized to the soil carbon sequestration and stabilization and, thus, to mitigate climate change processes.The studies were carried out in Sardinia (Italy) in three different cropping systems under Mediterranean condition: a wooded grassland in an agro-silvo-pastoral area; an intensive forage system in a Nitrate Vulnerable Zone and an artichocke organic farming system.The overall aim of this research was to evaluate the effects of different land uses and management practices such as presence of trees, type of fertilizer, crop residues, cover crop and rotation, on soil organic matter quality and stability through the determination of well known SOm quality indicators (DOM, WEOM, POMfree, POMoccluded and M-OM).The results demonstrated (i) the fundamental role of trees for the sustainability of the studied agroforestry systems and their positive effects on soil fertility, (ii) the direct and indirect influence of the type of fertilizer (slurry, manure and mineral) on the C balance and accumulation, mainly due to the different contribution to total C input that the soil receives and (iii) the key role of crop residues management and the cultivation of cover crops on C cycling and storage in organic artichocke systems.