EnvironmentRock dust, compost and biochar can all help capture carbon dioxide and boost crop yields when spread on soil but researchers are discovering they may be even more effective when used in combination 21 February 2025 Wilbourne Farm in VirginiaJames DinneenKade Wilbourne pulls a lever, and several tonnes of volcanic rock shoot out onto the field behind us in a fan of blue-grey dust. We are sitting in the cockpit of a tractor on the Wilbourne Farm in Mecklenburg County, Virginia. Normally, soybean and corn yields are the metrics that matter most here. But today, what counts is carbon.The soil on farms like this is already a major reservoir of carbon, contained in organic form in the bodies of microbes