Synergistic effects of multiple “good agricultural practices” for promoting organic carbon in soils: A systematic review of long-term experiments

Loss of soil organic carbon (SOC) from farmland is a key threat to the capacity of soils to provide ecosystem services and exacerbates climate change. In alignment with a published protocol, we conducted a review and meta-analysis of time series of SOC measurements in long-term agricultural experiments to study absolute SOC changes under different agricultural management regimes. Our results show that SOC in the upper 30 cm layer generally declined across long-term experiments (214 time data series in arable land across 23 sites in temperate to cold regions), but reducing tillage, adding organic amendments, diversifying crop rotations and avoiding bare fallows reduced losses. Furthermore, a net increase in SOC content is achieved when combining all four interventions. Applying multiple strategies for SOC preservation can unleash the potential for agricultural land to become a carbon sink while safeguarding agricultural yields for future generations.