Principal Investigator: Tim Griffis
Each year, on the order of 5×106 tons of synthetic nitrogen (N) fertilizer is applied in the US Corn belt to maximize crop yields. Unfortunately, there are several unintended environmental consequences associated with high N application rates. Agricultural lands leach nitrate (NO3) into water systems in the Mississippi and are the dominant contributor to hypoxia in the Gulf of Mexico. Furthermore, our recent research has revealed that headwater streams in agricultural watersheds are important, and poorly constrained sources of nitrous oxide (N2O), a potent greenhouse gas (GHG). Here, we propose to identify potential sites for N processing nodes within headwater stream networks to simultaneously manage N2O and NO3 using constructed wetlands. The scope of this proposed research will involve building upon our established research capacity that we have developed to identify potential N2O emissions hotspots. We will incorporate additional LiDAR, soils, land-use and stream data within a Geographic Information System (GIS) to identify optimal sites for establishing constructed wetlands in headwater stream networks that are characterized by high NO3 and N2O concentrations and suitable topography. We will use this product as a guide to select sampling locations where we will measure denitrification in native soils and sediments. Denitrification and ancillary water and soil quality data will be incorporated into a GIS data product. These data will support the local development of wetland design criteria, specifically focusing on NO3 and N2O load reductions.