Use of Relict Organic Soils on Restored Floodplains: Effects on Soil Pore Water Nitrogen Concentrations
Alexis Yaculak
University of Delaware
Newark, Delaware
Authors:
Alexis M Yaculak, Plant and Soil Sciences Department, University of Delaware, Newark Delaware
Shreeram P. Inamdar, Plant and Soil Sciences Department, University of Delaware, Newark Delaware
Jinjun Kan, Stroud Water Research Center, Avondale, Pennsylvania
Marc Peipoch, Stroud Water Research Center, Avondale, Pennsylvania
In the Mid-Atlantic region of the US, historic and contemporary land use practices have resulted in large deposits of legacy sediment-filling valley bottoms. Buried beneath these legacy sediment deposits are organic-rich (C and N) soils from pre-colonial surficial marshes, bogs, or wetlands. Erosion of overlying legacy sediments and associated nutrients is one of the key contributors of water pollution, especially in the mid-Atlantic US. Current stream and floodplain restoration practices aim to remove overlying legacy sediments and enhance the hydrologic connection and nutrient exchange between the stream and floodplain. The buried organic horizon is not typically considered in these restorations and is removed and discarded during this process. These relic organic layers could be leveraged to improve nitrogen removal through denitrification by the “daylighting” of these soil horizons on floodplains and their hydrologic reconnection to the stream. Relict soils could also help bring back historic soil microbiomes and enhance and “rewild” the restored floodplains. This study looks to compare the change in floodplain soil pore water nitrogen (N) concentrations for relict, hydric soils against contemporary wetland soils and restored floodplain soils. While this study is still ongoing, it is expected that initially following restoration, floodplain soil pore water N concentrations will be higher for contemporary wetland and relict soils versus restored floodplain soils. Additionally, following restoration there will be an increase in floodplain soil pore water N due to inorganic release from the relict soils organic rich (C and N) hydric layers. It is also expected that it will take 1-2 years for relict soil pore water N concentrations to decrease and match those for adjoining non-relict wetlands.
About Alexis Yaculak
Alexis Yaculak is a second-year PHD student at the University of Delaware, College of Agriculture and Natural Resources in the Water Science and Policy program. She joined the program in fall of 2022 in the lab of Dr. Shreeram Inamdar. Her research focuses on examining the impact that daylighting of relic hydric soils can have on floodplain restorations, specifically in the mid Atlantic region of the United States. She holds a Bachelor's of Science in Geology from the University of Maryland, where she worked as a lab assistant under Dr. Sujay Kaushal, completing a thesis studying the mobilization of redox sensitive elements in a regenerative stormwater conveyance system.
