Global crop production increase by soil organic carbon

Soil organic carbon sequestration has been promoted to combat climate change while improving soil fertility. However, its quantitative contribution to crop productivity has proven elusive. Using data from 13,662 controlled field trials with 66,593 treatments across a broad range of soils, climates and management practices, we here show that yields increase with increased soil organic carbon, until no further increase (p < 0.05) occurs above mean optimum soil organic carbon of 43.2-43.9 g kg(-1) for maize, 12.7-13.4 g kg(-1) for wheat and 31.2-32.4 g kg(-1) for rice. Sequestering soil organic carbon is one-fifth as effective (that is, 80% less) as nitrogen fertilization for improving crop yield where soil management is optimized. By increasing soil organic carbon beyond current technology to optimum levels, global production of the three most important staple crops increases by 4.3% (sufficient to provide calories for 640 million people). However, currently available management practices would increase crop production by only 0.7% once other production constraints have already been addressed. Therefore, yield improvements under currently available technologies are unlikely to drive adoption of soil organic carbon sequestration globally, except in hot-spot regions where crop production benefits most, or unless novel practices that allow greater soil organic carbon sequestration beyond current limitations can further increase yields cost-effectively.