Topsoil organic carbon content in three representative silvopastoral areas at different elevation in Sardinia

Sardinia is an ancient island in the centre of Mediterranean Sea. It has complex geology from 400 million years and few zones in the world exhibit such a large variety (igneous, sedimentary and metamorphic) of rocks in a restricted area. Plant residues and microorganism affect microbial growth, and decomposition contributes to soil organic matter. Soil organic carbon (SOC) is a major component of soil organic fraction, positively affecting soil properties. The aim of this work was to determine organic carbon contents in topsoil in three regions of Sardinia (Italy) representative of Mediterranean environments and the variation in SOC of sites along an elevation gradient. The SOC concentration in the topsoil layer ranged from 8.8 to 47.7 g kg -1 in Arci-Grighine, from 30.0 to 71.0 g kg -1 in Montepisanu and from 13.2 to 73.4 g kg -1 in Ogliastra, differences were proportional with elevation. The results highlight that elevation is strongly correlated to SOC concentration in the topsoil.