Soil quality attribute time paths: Optimal levels and values

We develop a dynamic soil quality model to evaluate optimal cropping system s in the northern Great Plains. Modeling soil quality attributes is feasibl e, and attribute model results apply to a wide range of soils. A crop produ ction system with continuous spring wheat and direct planting is the most p rofitable system. This system has low soil erosion and high quality attribu tes, indicating the benefits of increased soil quality exceed the higher ma intenance costs. On-site value of additional soil organic carbon (OC) range s from $1 to $4/ton OC/hectare/year. These values for soil OC impact the op timum tillage practice, but not the crop rotation.