UMES Permeable Reactive Barriers

Nutrient leaching is a process by which percolating rainwater carries dissolved nutrients down through the soil profile.

Leached nutrients that reach shallow groundwater may then move towards surface water features like drainage ditches and streams. Nitrogen and phosphorus are two important nutrients required for crop growth. However, when these nutrients leave agricultural fields during and after heavy rain, they pose a risk to water quality. Poor water quality is a health risk to humans and ecosystems. To address this concern, University of Maryland Eastern Shore (UMES) researchers are studying permeable reactive barriers.

Results will help to determine how effective the barriers are at minimizing the amount of leached nutrients that reach sensitive surface waters. Two types of permeable reactive barriers are currently being studied at UMES: gypsum curtains and sawdust walls. Gypsum curtains are designed to capture dissolved phosphorus moving in shallow groundwater. Sawdust walls detain groundwater and promote the microbial conversion of nitrate. Nitrate, the most common form of dissolved nitrogen, is converted into inert nitrogen gas (N₂). Practices such as these may enable farmers to reduce nutrients in runoff before it enters waterways, promoting better nutrient stewardship and reducing harm to aquatic life.

“Farmers are often interested in making their living off of farming the land, but they also have a great interest in protecting the land.  Part of our concern is the environmental issues, and that affects farmers as well.  They are able to maintain that environmental stewardship through the installation of some of these practices that help to reduce nutrients coming off of their fields.”

- Dr. Amy Collick, Assistant Research Professor at University of Maryland Eastern Shore

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