Carbon Farming in Agricultural Systems: A Systematic Review of Soil Organic Carbon Dynamics and Soil Health Outcomes

Carbon farming practices (CFPs) are increasingly promoted to enhance soil organic carbon (SOC) sequestration while improving soil health. However, field-based evidence remains fragmented across practices, environments, and study designs. This systematic review synthesised evidence from 107 field-based studies conducted in 31 countries between 2010 and 2025. It evaluated the effects of widely implemented CFPs on SOC and examined how these responses were associated with physical, chemical, and biological indicators of soil health. CFPs were grouped into six categories: tillage, fertilisation, organic amendments, biochar, crop diversification, and cover crops. Across the included studies, reported positive responses ranged from 3.5% to 90.0% for SOC concentration and from 5.0% to 83.5% for SOC stocks. These descriptive ranges were not directly comparable because the studies differed in sampling depth, duration, baseline conditions and reporting method. SOC gains were reported mainly in the upper 0–20 cm. Direct carbon-input practices, particularly organic amendments and biochar, tended to show larger reported concentration responses, whereas tillage, fertilisation, crop diversification and cover crops operated mainly through slower plant- and system-mediated pathways. SOC increases often co-occurred with improvements in soil structure, nutrient status, and microbial activity, supporting its role as a key soil health indicator. However, inconsistent reporting of SOC fractions, depth distribution, and soil health indicators limits the assessment of long-term carbon persistence and overall soil functioning. Overall, carbon farming (CF) shows strong potential to enhance SOC and soil health, but outcomes remain context-dependent and require long-term, depth-resolved, and integrated monitoring approaches.