The report presents a systematic review of meta‑analyses that quantify the environmental effects of a range of sustainable farming practices. The authors first identified synthesis papers that reported statistically significant results for the impacts of interest – greenhouse gas (GHG) emissions, soil organic carbon (SOC) sequestration, ammonia emissions, nutrient leaching and runoff, and the overall agricultural nutrient balance. Using a majority fast‑track method, they extracted coefficients from the most appropriate meta‑analyses for each practice‑impact combination. The extracted coefficients are compiled in a summary table that lists, for every farming practice and environmental outcome, the number of coefficients obtained and the section of the report where the detailed results are presented. Empty cells in the table indicate either a lack of statistically significant evidence or a gap in the literature for that particular combination.

The technical findings are organised by practice type. Agroforestry practices are shown to increase SOC, with the extracted coefficients indicating a positive trend across several crop‑soil‑region sub‑groups. Organic farming systems are analysed in three sub‑categories. For greenhouse gas emissions, the meta‑analyses reveal a reduction relative to conventional systems, with coefficients ranging from a 10 % to 30 % decrease in CO₂‑equivalent emissions depending on crop type and management intensity. SOC responses in organic cropping systems are generally positive, with coefficients suggesting a 5 % to 15 % increase in SOC stocks over a decade. In organic livestock systems, the impact on SOC is more variable, with some studies reporting modest gains and others showing negligible change. Nutrient leaching and runoff are consistently lower in organic systems, with coefficients indicating reductions of 20 % to 40 % compared to conventional practices.

Low‑ammonia fertilisation techniques, such as controlled‑release formulations and precision application, are evaluated for their effect on ammonia emissions. The extracted coefficients show a substantial reduction, typically 30 % to 50 % lower ammonia volatilisation than standard mineral fertilisation. These techniques also improve the nutrient balance by increasing nitrogen use efficiency, with coefficients indicating a 15 % to 25 % improvement. However, the impact on nutrient leaching and runoff is mixed; some studies report a slight increase due to higher nitrogen availability, while others show no significant change.

Enhanced‑efficiency fertilisers (EEFs) are examined for GHG emissions, ammonia emissions, nutrient balance, and leaching. The meta‑analyses reveal that EEFs can reduce GHG emissions by 10 % to 20 % and ammonia emissions by 25 % to 35 %. Nutrient balance improvements are modest, with coefficients indicating a 10 % increase in nitrogen use efficiency. Leaching and runoff reductions are generally small, with coefficients ranging from 5 % to 15 % lower losses.

Organic fertilisation, green manuring, and biochar amendments are also covered. Organic fertilisers tend to lower GHG emissions by 5 % to 15 % and increase SOC by 5 % to 10 %. Green manuring shows similar benefits for SOC and nutrient balance, with coefficients indicating a 10 % to 20 % increase in SOC and a 15 % to 25 % reduction in nutrient leaching. Biochar amendments are highlighted for their potential to sequester carbon, with coefficients suggesting a 10 % to 30 % increase in SOC depending on biochar type and application rate, and a 20 % to 40 % reduction in ammonia emissions.

The collaboration behind the report is led by the Joint Research Centre (JRC) of the European Commission, with contributions from partner research institutions across the EU. The JRC coordinated the systematic review, data extraction, and synthesis, while partner organisations provided expertise in specific farming systems and regional data. The project was funded by the European Union under the Horizon programme, with a timeframe spanning from 2023 to 2024. The report’s findings are intended to inform EU policy makers on the environmental trade‑offs of sustainable agricultural practices and to support the development of evidence‑based guidelines for climate‑friendly farming.