Integrating GIS-based field data and farm modeling in a watershed to assess the cost of erosion control measures: An example from southwest Germany

Policy measures regulating agricultural production are becoming increasingly important in the control of erosion and water runoff. In order to enable planners and other authorities to implement such measures efficiently, detailed information regarding the relevant costs and benefits is necessary. However, economic models to date have tended to utilize a spatial resolution that is insufficient to reveal the effects of such measures on a micro scale. Farming practices, like cross-slope cultivation, filter strips, or field divisions, exert varying impacts on small spatial structures. The benefits and costs of such measures depend to a large degree on local conditions, such as field size and slope. Environmental models as well as economic modeling must take these factors into account. This paper presents a novel approach called CULTIVASIM that directly incorporates field-level topographic and geometric data into a farm economic model. This allows researchers to gain insight into the cost structure of these tasks on a field level as well as a farm level when considering whole-farm adaptation possibilities. Results show that while falter strips lead to relatively uniform costs in relation to area, the costs of field division and cross-slope cultivation vary greatly depending on the field geometry. This information should be included when planning control measures and designing compensation schemes. This new model approach can be used to calculate the economic costs and benefits of using precision conservation practices across the landscape.