Integrated assessment modeling reveals near-channel management as cost-effective to improve water quality in agricultural watersheds.

Despite decades of policy that strives to reduce nutrient and sediment export from agricultural fields, surface water quality in intensively managed agricultural landscapes remains highly degraded. Recent analyses show that current conservation efforts are not sufficient to reverse widespread water degradation in Midwestern agricultural systems. Intensifying row crop agriculture and increasing climate pressure require a more integrated approach to water quality management that addresses diverse sources of nutrients and sediment and off-field mitigation actions. We used multiobjective optimization analysis and integrated three biophysical models to evaluate the cost-effectiveness of alternative portfolios of watershed management practices at achieving nitrate and suspended sediment reduction goals in an agricultural basin of the Upper Midwestern United States. Integrating watershed-scale models enabled the inclusion of near-channel management alongside more typical field management and thus directly the comparison of cost-effectiveness across portfolios. The optimization analysis revealed that fluvial wetlands (i.e., wide, slow-flowing, vegetated water bodies within the riverine corridor) are the single-most cost-effective management action to reduce both nitrate and sediment loads and will be essential for meeting moderate to aggressive water quality targets. Although highly cost-effective, wetland construction was costly compared to other practices, and it was not selected in portfolios at low investment levels. Wetland performance was sensitive to placement, emphasizing the importance of watershed scale planning to realize potential benefits of wetland restorations. We conclude that extensive interagency cooperation and coordination at a watershed scale is required to achieve substantial, economically viable improvements in water quality under intensive row crop agricultural production.

Socio-psychological factors influencing intent to adopt conservation practices in the Minnesota River Basin.

In the upper Midwestern United States, one of the central goals of agri-environmental policy is to reduce environmental and water quality degradation resulting from agriculture without sacrificing production. The primary tool available to policymakers is offering farmers incentives to voluntarily adopt more conservation practices, often known as Best Management Practices (BMPs). Using the Theory of Planned Behavior (TPB) and Diffusion of Innovation (DoI) frameworks, we surveyed 2000 agricultural landowners in the Minnesota River Basin to explore the socio-psychological drivers of the adoption decisions for specific BMPs such as wetlands, cover crops, and nutrient management. We found that attitude (both favorable and unfavorable), awareness of environmental problems, and appreciation of ecosystem services significantly affected landowners' adoption intentions for the three BMPs. We applied landowner segmentation analysis and compared both the socio-psychological and socio-demographic features among different landowner segments (i.e. environmentally-conscious landowners, engaging-absentee landowners, and adoption-averse landowners). Our study can inform the development of targeted conservation policies for various landowner types to motivate BMPs adoption.

Forward-looking farmers owning multiple potential wetland restoration sites: implications for efficient restoration.

Wetland restoration can increase the provision of multiple non-market ecosystem services. Environmental and socio-economic factors need to be accounted for when land is withdrawn from agriculture and wetlands are restored. We build multi-objective optimization models to provide decision support for wetland restoration in the Le Sueur river watershed in Southern Minnesota. We integrate environmental objectives of sediment reduction and habitat protection with socio-economic factors associated with the overlap of private land with potential wetland restoration sites in the watershed and the costs representing forward-looking farmers voluntarily taking land out of agricultural production in favor of wetland restoration. Our results demonstrate that the inclusion of these factors early on in the restoration planning process affects both the total costs of the restoration project and the spatial distribution of optimally selected wetland restoration sites.