What Influence Does Conventional Tillage Have on the Ability of Soils to Sequester Carbon, Stabilise It and Become Saturated in the Medium Term? A Case Study in a Traditional Rainfed Olive Grove

Soils have the capacity to store three times more carbon (C) than atmosphere. This fact has focused scientific and governmental attention because it is one way mitigate climate change. However, there comes a time when of soils C reaches limit, considering soil organic (SOC) saturation. In Mediterranean area, agricultural are traditionally exposed conventional tillage (CT), causing properties quality degradation. Therefore, this study aimed determine whether CT modifies storage (carbon saturation), linked mineral fractions <20 µm in olive grove area over 15 years. The results showed losses SOC stock (SOC-S) period studied. Moreover, significantly affected aggregate grain size, reducing percentage small macro-aggregates (2000–250 µm) by 51.1%, 32.9%, 46.6%, 50.6% for Ap, Bw, BC, horizons, respectively, promoting an increase fine (large micro-aggregates (250–53 µm), silt + clay fraction (53–20 (<20 µm)). After years, fractionation decrease concentration within large macro-aggregate (>2000 38.6% Bw horizon; however, time, 33.5%, was observed Ap horizons. increasing trend continued fractions. Concerning bound evolution with led sequestration first horizons 44.7% (Ap horizon) 42.9% (Bw horizon), depth (BC 31.3%. Finally, total saturated (T-SOC-Ssat), after experienced 30.5 Mg ha−1, these conditioned deficit (SOC-Sdef), potential sequester carbon, 15.2 ha−1 With results, we can affirm that effect medium term degradation low concentrations, therefore made possible soils, application sustainable management practices, high become sinks.