Assessment of carbon sequestration and the carbon footprint in olive groves in Southern Spain

Tree plantations are characterized by their ability to remove CO2 from the atmosphere and store it in a stable manner in tree structures (trunks, roots and branches) as well as in the soil. The study was conducted in Southern Spain in olive groves and covering an area of 1121 ha, where 22 homogenous plantation units were selected. The Picual and Arbequina varieties were assessed in intensive, super-intensive and conventional plantations as well as in rainfed and irrigated plantations. The net carbon (C) balance in the olive tree plantations was clearly positive, especially in intensive and super-intensive plantations (2.05 and 4.10 Mg C ha(-1) yr(-1) on average for all plantations studied). These results are significant for life-cycle evaluations of olive oil and for obtaining the C footprint of olive oil as a final product. Improved practices for soil management, such as the use of conservation tillage and cover crops and reincorporating pruning residues into the soil, can notably increase the net C balance in tree plantations and may even double it in amount. Thus, including the C sequestration rate of olive tree plantations can increase the accuracy of C footprint estimations for olive oil and represents a key factor in marketing the final product according to its environmental benefits.