Using Plant Selection to Control Pollution Tradeoffs in Agricultural Wetlands
Using Plant Selection to Control Pollution Tradeoffs in Agricultural Wetlands

Abstract

Creating and restoring wetlands on farms can reduce nutrient export from row-crop agriculture. While agricultural wetlands improve water quality, wetlands may also be a source of potent greenhouse gases, such as nitrous oxide (N2O) and methane (CH4), that contribute to climate change. We posit that strategic targeting of wetland plant species based on composition of plant organic residues will maximize complete denitrification, while reducing the release of potent greenhouse gases. By influencing the composition and long-term fate of soil organic matter (SOM), composition of plant organic residues will directly influence the lability of SOM in underlying soils. This lability will then regulate the tradeoff between water quality improvements and greenhouse gas emissions. To test this hypothesis, we will 1) measure denitrification, sulfate reduction, and GHG production rates across wetland soils underlying different plant communities and when plant organic residues are added from different species at multiple stages of decomposition in microcosm experiments 2) characterize the biochemical composition of added plant organic residues, the nature of SOM, and other soil properties 3) investigate the link between plant organic residues, plant-derived SOM, and wetland function with statistical modeling. Our proposed model are emergent plant communities that border a shallow impoundment that drains surrounding farmland in northwest Indiana. With the focus on identifying vegetation-related controls of water quality improvements and GHG production, this research has the potential to guide wetland managers and restoration engineers in maximizing the benefits of embedding wetlands in agricultural landscapes through strategic planting.