7 Min Read (Reuters) - When Microsoft Corp made a massive purchase of carbon credits in January, it turned to a relatively new source: farmers who plant crops meant to trap carbon in the soil. A cover crop of tiller radishes is seen in a corn field in Butler County, Nebraska, U.S. April 6, 2021. Lukas Fricke/Handout via REUTERS The credits are financial instruments generated by projects that reduce or avoid the release of greenhouse gases, such as solar farms or tree-plantings. The projects’ owners can sell the credits to companies who then use them to make claims of offsetting the climate impact of their operations.