This course will review the explore the current knowns and unknowns of soil carbon, focusing on whether soils can be a sink of carbon in agricultural (e.g., cropping and range) systems. The first half of the semester will focus on the different types of carbon in soil, the origin of these different carbon fractions, and how they are measured. The second half of the semester will focus on how these types of carbon are (or are not) affected by management in cropland and rangeland systems, as well as whether management can be used to increase carbon sequestration in agricultural settings.