Soil pH and carbon storage: Organic amendments that fix acidity may lock carbon and boost yields

New research in Advanced Science analyzed 251 field trials and found that replacing part of synthetic fertilizer with manure, biochar, or compost shifts soil pH toward neutral, and that pH change itself stores soil organic carbon even before counting the carbon added by the amendments. Acidic soils cover roughly half of global croplands and have lost up to 20% of soil organic carbon, so the finding could matter for both crop yields and carbon sequestration programs. Separate liming trials confirmed the pH effect without added organic carbon, and microbial biomass appeared to be the main driver. The authors argue carbon crediting frameworks should recognize pH-mediated carbon stabilization as a legitimate sequestration pathway. That would change how soil carbon projects are measured and paid.