This upload contains the supplementary information files for the systematic review and meta-analysis of time series data of Soil Organic Carbon (SOC) measurements in long-term field experiments performed in 'Synergistic effects of multiple “good agricultural practices” for promoting organic carbon in soils: A systematic review of long-term experiments.' by López i Losada et al. 2025 The protocol for the systematic review can be found in 'Which agricultural management interventions are most influential on soil organic carbon (using time series data)?' by Haddawat et al. 2016 [DOI: 10.1186/s13750-016-0053-z] R scripts used to calculate net SOC change rates from individual time series (regressions.R) and effect sizes from management interventions (metanalysis.R) are provided along with auxiliary files (time_labs.xlsx, statistics.xlsx, and SOCdata.xlsx). Supplementary files S1, S2, and S4 provide an overview of the systematic review method and its findings. Supplementary file S1 is also an auxiliary file to run the R scripts. Supplementary files S3 and S6 contain the output summary of statistics from the analysis performed in the R scripts. This project was financed by the Mistra Council for Evidence-Based Environmental Management (EviEM), FORMAS Grant 2018-01726 (to Y. Clough) and the strategic research area Biodiversity and Ecosystems in a Changing Climate (BECC).