SOIL QUALITY ATTRIBUTE TIME PATHS: OPTIMAL LEVELS AND VALUES

We develop a dynamic soil quality model to evaluate optimal cropping systems in the northern Great Plains. Modeling soil quality attributes is feasible, and attribute model results apply to a wide range of soils. A crop production system with continuous spring wheat and direct planting is the most profitable system. This system has low soil erosion and high quality attributes, indicating the benefits of increased soil quality exceed the higher maintenance costs. On-site value of additional soil organic carbon (OC) ranges from $1 to $4/ton OC/hectare/year. These values for soil OC impact the optimum tillage practice, but not the crop rotation.