Design and Management of On-Farm Wetlands for Water Quality and Climate Regulation

View the project final report

Commodities

Practices

• Natural Resources/Environment: wetlands

Wetland creation and restoration are an integral part of overall nutrient management strategies for watersheds with intensive row-crop agriculture, because wetlands are effective sinks for nutrients. Many of the same environmental conditions that support the capacity of wetlands to capture nutrients also stimulate release of methane (CH₄) and nitrous oxide (N₂O), which are potent greenhouse gases (GHGs) that drive climate change. Climate change threatens the natural resource base on which agriculture depends. To balance the looming threat of climate change and the need to protect sensitive downstream ecosystems from pollution, we need to design and manage wetlands to reduce CH₄ and N₂O emissions while maintaining water quality benefits. My project, “Design and Management of On-Farm Wetlands for Water Quality and Climate Regulation,” will address this demand through research and outreach efforts.

Two main factors of wetland design and management are vegetation and hydrology. Variability in water quality and climate regulation functions have been previously linked to vegetation and water table management (WTM), but there is considerable uncertainty about the mechanisms that drive these differences. This research will address these uncertainties by isolating the effects using experimental mesocosms and novel integration of biogeochemical methods. The effects of plant species and hydrology will be assessed by measuring CH₄, CO₂, and N₂O fluxes and nutrient retention in mesocosms. The mechanisms that explain differences across treatments will be identified by measuring plant, soil, and hydrologic characteristics and performing multivariate analyses to identify characteristics that predict wetland response. A major outcome from this research will be the development of actionable guidelines for plant selection and WTM of wetlands that effectively treat agricultural drainage while reducing GHG emissions.

Project outcomes related to outreach include increasing actionable knowledge about how wetland plant species and WTM can be leveraged to maximize water quality and climate regulation benefit, addressing farmers’ concerns about profitability and cost of wetlands, and increasing knowledge of K-12 students of the role of wetlands in sustainable agriculture. These objectives will achieved through a combination of Extension and journal publications, a field day, and educational videos. The effectiveness of these outreach efforts will be evaluated based on number of attendees and course evaluations from the field day, number of K-12 students reached, number of publications, and level of social media engagement for virtual products. The achievement of research and outreach outcomes will support farmers in meeting nutrient reduction goals while limiting contributions to climate change.

The primary learning outcome is to increase the actionable knowledge of farmers and wetland practitioners about how wetland plant species and water table management can be leveraged to maximize water quality and climate regulation benefits. These wetland practitioners may be employed by the NRCS, environmental consulting firms, and non-profit agencies that invest in wetland restoration, such as Ducks Unlimited and The Nature Conservancy. NRCS engineers and other wetland practitioners are the primary interface between county agencies, farmers, and non-profits who might be proponents of wetland adoption. A secondary learning outcome is to address farmers’ concerns about profitability and costs of on-farm wetlands. Another learning outcome is to increase knowledge and awareness of K-12 students of the role of wetlands in sustainable agriculture.

If the learning outcomes are effectively met, I anticipate the following actions: wetland practitioners will incorporate this guidance into future wetland designs to make planned wetlands more sustainable, farmers will adapt management of existing wetlands (e.g. installing water control structures or removing certain plant species) based on management guidance to make wetlands more sustainable, more farmers in the North Central region will implement wetlands for nutrient reduction, and more K-12 students will consider pursuing careers in sustainable agriculture. Although these action outcomes are anticipated, tracking these changes in behavior is beyond the proposed scope of the project.