Project Title

Nutrient export from a proximal intermittent stream draining EKU Meadowbrook Farm, Madison County, Kentucky

Presenter Hometown

Richmond, KY

Major

Geology

Department

Geosciences

Degree

Undergraduate

Mentor

Walter S. Borowski

Mentor Department

Geosciences

Abstract

Agricultural activities contribute significant amounts of nutrients that contaminate surface and subsurface water. Eastern Kentucky University Meadowbrook Farm seeks to decrease its export of nutrients into Muddy Creek. The first step in this process is to determine nutrient export at present, before sequestration efforts take place. Here we estimate the export of phosphate, nitrate, and ammonium during three rain events in summer 2017 from a proximal, intermittent stream (the BRC). This stream drains a representative portion the Farm, receiving water from a dairy complex, pasture, and cropland.

To estimate nutrient export, both discharge and nutrient concentration must be determined. We measure discharge over an instrumented dam during rain events. Nutrient concentration is measured in water samples using established colorimetric methods: ascorbic acid (phosphate), cadmium reduction (nitrate), and sodium hypochlorite (ammonium). Discharge and concentration data were parsed into 30-second time steps, and we used a cubic spline application (grafted into MS Excel) to produce a continuous function for each parameter. The integrated area under the discharge and concentration curves yielded total solute mass for the events.

Total discharge volume and nutrient export are somewhat proportional but results vary over several orders of magnitude. The largest rain event, Tropical Storm Cindy, exported 3.1 kg phosphorus was (P) as dissolved orthophosphate, and 6.3 kg nitrogen (N) as dissolved nitrate (5.3 kg) and ammonium (1.0 kg). In order to better determine the relationship between total discharge and nutrient export, we intend to capture many more rain events during the field season of 2018.

Presentation format

Poster

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COinS
 

Nutrient export from a proximal intermittent stream draining EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities contribute significant amounts of nutrients that contaminate surface and subsurface water. Eastern Kentucky University Meadowbrook Farm seeks to decrease its export of nutrients into Muddy Creek. The first step in this process is to determine nutrient export at present, before sequestration efforts take place. Here we estimate the export of phosphate, nitrate, and ammonium during three rain events in summer 2017 from a proximal, intermittent stream (the BRC). This stream drains a representative portion the Farm, receiving water from a dairy complex, pasture, and cropland.

To estimate nutrient export, both discharge and nutrient concentration must be determined. We measure discharge over an instrumented dam during rain events. Nutrient concentration is measured in water samples using established colorimetric methods: ascorbic acid (phosphate), cadmium reduction (nitrate), and sodium hypochlorite (ammonium). Discharge and concentration data were parsed into 30-second time steps, and we used a cubic spline application (grafted into MS Excel) to produce a continuous function for each parameter. The integrated area under the discharge and concentration curves yielded total solute mass for the events.

Total discharge volume and nutrient export are somewhat proportional but results vary over several orders of magnitude. The largest rain event, Tropical Storm Cindy, exported 3.1 kg phosphorus was (P) as dissolved orthophosphate, and 6.3 kg nitrogen (N) as dissolved nitrate (5.3 kg) and ammonium (1.0 kg). In order to better determine the relationship between total discharge and nutrient export, we intend to capture many more rain events during the field season of 2018.