Optimizing Spatial Land Management to Balance Water Quality and Economic Returns in a Lake Erie Watershed

Significant reductions in phosphorous (P) inputs from cropland are needed to address the re-eutrophication of Lake Erie. Previous studies aimed at addressing non-point source pollution have primarily analyzed the effectiveness of conservation practices (CPs) as land-management strategies. However, the effectiveness and efficiency of these practices have not been compared to those of possible land-use changes. We develop a spatially explicit integrated modeling approach that compares the effectiveness and economic efficiency of alternative spatially optimal land-use and -management strategies for P abatement in the Sandusky River watershed. Using the Soil and Water Assessment Tool and data on costs and profits from crop and forest production and urban development, we evaluated joint impacts on P reduction and economic-returns for optimized land-use changes and/or implementation of CPs in the watershed. Results showed a combination of both CPs and land-use changes are likely required to meet current abatement targets for dissolved reactive phosphorus. Additionally, the combination of these approaches can generate a positive, synergistic effect on economic efficiency in meeting key policy targets. This is largely because the combined strategy will establish CPs on the most productive cropland, while achieving greater nutrient reduction through land-use change away from corn-soybean rotations on less productive lands.