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Agriculture represents about 11% of global anthropogenic greenhouse gas emissions (GHGe). Many climate change mitigation strategies have been evaluated in Mediterranean agroecosystems, including their soil organic carbon sequestration potential. High residue yielding old varieties could constitute a useful alternative, especially for organic farming, which lacks specific genetic material. In this study, old and modern wheat varieties were evaluated under organic (ORG) and conventional (CON) management during a 3-year field experiment under rainfed Mediterranean conditions. Field measurements of biomass components, literature emission factors, and soil organic carbon modeling were combined in an attributional Life Cycle Assessment, in order to estimate GHGe from “cradle to farm gate”. The resulting yield-based carbon footprints of old wheat varieties were significantly lower than those of modern varieties both under CON management, decreasing from 263 to 144 g CO 2 e kg −1 , and under ORG management, decreasing from 29 to −43 g CO 2 e kg −1 . Our results indicate that climate change mitigation strategies in Mediterranean rainfed cereal cropping systems should focus on diminishing GHGe from machinery and fertilizer use, and promoting carbon sequestration. The combination of organic management and old cereal varieties can constitute a promising climate change mitigation strategy in these systems, as low area-scaled GHGe of organic management are combined with enhanced carbon sequestration and a good yield performance of old varieties under these conditions. [ABSTRACT FROM AUTHOR]

Vineyards are usually cultivated in soils characterised by low soil organic carbon (SOC) content and have high risks of soil erosion and degradation. Increasing SOC stocks in these cropping systems has the potential to contribute to climate change mitigation through SOC sequestration and to enhance soil quality. We conducted a meta-analysis and compared the SOC stock response ratio, the SOC stock rate of change, and the SOC sequestration rate in vineyards under different SOC sequestration (SCS) practices relative to conventional management. SCS practices included organic amendments (OA), biochar amendments (BC), returning pruning residues to the soil (PR), no-tillage (NT), cover cropping (CC), and several combinations of these practices. The average SOC sequestration rate of SCS management was 7.53 Mg CO 2 -eq. ha−1 yr−1 to a 30-cm soil depth. The highest SOC sequestration rate (11.06 Mg CO 2 -eq. ha−1 yr−1) was achieved under a combination of OA+NT and the lowest (2.82 Mg CO 2 -eq. ha−1 yr−1) was observed under PR treatments. Field experiments performed in particularly hot and dry bioclimatic zones were associated with lower SOC sequestration rates relative to those performed in more temperate areas. The high SOC sequestration rates obtained for many SCS practices, and the large land area dedicated to viticulture worldwide (7.45 Mha), imply that the adoption of SCS practices in vineyards can contribute to the global efforts to offset atmospheric greenhouse gas concentrations via SOC sequestration to mitigate climate change. • Effects of soil carbon sequestration (SCS) practices were assessed in vineyards using a meta-analysis. • All SCS practices led to soil organic carbon (SOC) accumulation in viticultural soils. • The average SOC sequestration rate was 7.53 Mg CO 2 -eq. ha−1 yr−1. • The impact of SCS management on SOC stocks was climate-dependent. [ABSTRACT FROM AUTHOR]