Rothamsted Research reviewed 422 studies on conservation agriculture and greenhouse gas emissions. No-till and reduced tillage consistently lowered carbon dioxide and sometimes cut nitrous oxide. Mulching and cover crops helped soil health but could raise emissions when decomposing material boosted microbial activity. Fertiliser results varied, with nitrogen application rate a major driver of nitrous oxide. The study also linked legume-based rotations to lower CO2 than continuous cereals. Researchers stressed that local soil and rainfall decide whether a practice cuts or adds emissions, so blanket policy advice is risky. They also flagged a lack of long-term field data in Africa and called for more standardised reporting.
