Do you ever wonder how students use the White Clay for research? Recently, I sat down with fellow student Kelsey Moxey, a University of Delaware (UD) Master’s candidate in the interdisciplinary water science and policy program, to discuss her work in the White Clay. Kelsey studies nutrient dynamics in watersheds using geospatial analysis. Put simply, she examines how nutrients are distributed across the land surface, focusing specifically on mushroom farms within the Christina River Basin. Kelsey explains why her work is important, and how it will have a positive impact on the White Clay.
Q: How did your research project get started and what was the initial motivation behind it?
A: In the fall of 2014, I began working as a research assistant for Dr. Luc Claessens in the UD Geography Department. One of Dr. Claessens classes had previously conducted a water quality analysis in the White and Red Clay Creeks, which revealed high nitrate levels in both watersheds. With these results, interest emerged to identify where the prominent nutrient sources were located.
Q: What are conventional sources of nitrates? Where do they come from?
A: Nitrogen is a naturally occurring nutrient, but it can also be introduced into the environment by applications such as sewage and fertilizers. Nitrate, and other forms of nitrogen, can enter water bodies as the result of runoff. In any watershed, landscape uses greatly impact water quality. In the White Clay Creek watershed, nearly one-third of the land cover is agricultural and in southeastern Pennsylvania in particular, mushroom farming is a long established and widespread industry. I chose to focus on these particular agricultural areas since mushroom growing processes are usually associated with large quantities of nitrogen.
Q: Can you elaborate on the details of mushroom production?
A: Mushrooms are fungi, not plants, and therefore are cultivated somewhat uniquely. Growing mushrooms require the input of a nutrient rich compost. This mushroom compost contains a variety of components including organic nutrient sources (such as horse and or poultry manure), water, and binding materials (think: hay, woodchips or sawdust, cocoa shells). The fresh compost is then placed in beds in growing houses to facilitate the growth of mushrooms. During growth, the mushrooms take up water and some of the nutrients in the substrate; the leftover material is then either disposed of or set out on the land.
Q: What are some of the methods and tools used to understand where compost is being applied?
A: I am using remote sensing, a sub-category of geographical information systems (GIS) (i.e. mapping) to look at the Christina River watershed, which encompasses White Clay. In geographic research, remote sensing is a technique used to obtain information about objects or areas from a distance, typically from aircraft or satellites. Remote sensing has a wide variety of applications and uses in many different fields. The satellite I rely on for data collection is called LANDSAT, which through the United States Geological Service (USGS), provides imagery of the earth’s surface for analysis. The satellite essentially takes pictures of the land using sensors that detect energy being reflected at different wavelengths. Different land uses have varying wavelength signatures. I first looked at areas of known mushroom compost applications to determine its signature wavelength based on soil moisture content. Then I used data from the satellite images to distinguish other potential land applications of mushroom compost by identifying other areas with the same wavelength.
Q: What are the principal goals of the research?
A: In the geography field, research investigations are often concerned with questions that begin with “where?”. The major objective of my research is to detect agricultural areas of high organic matter content, which can subsequently indicate high nutrient content. Using soil moisture to identify where nitrogen hotspots associated with compost applications could be located is one way to do this. Hotspots can be defined in this situation as areas containing elevated nitrogen concentrations. My ultimate goal is to create a map of all the potential nitrogen hotspots in the basin.
Q: How will this research help to improve watershed health in the future?
A: Identifying nitrogen hotspots on the land can lead to improved implementation of best management practices (BMPs) and protection of our waterways. Determining these locations will improve our comprehension of the geographic or spatial extent of the pollutants in the watershed. Ultimately, the hope is that this will lead to more cost effective solutions for nutrient reduction through site-specific management. Tailoring reduction strategies to specific areas and their specific needs eliminates unnecessary costs, which is always a goal in managing our water resources. Additionally, this research can help the watershed to meet TMDL goals, an added benefit for the 130,000 people who call the White Clay home and those who rely on it for their drinking water.
Kelsey’s research illustrates the connectivity of land use impacts on water quality. She hopes this project will contribute in helping other researchers, scientists, managers, and policymakers better guide future strategic planning in the watershed. Understanding how nutrient hotspots are dispersed in the landscape enhances the scientific body of knowledge related to watershed dynamics. It’s important we remember that research projects like this create knowledge. The more we know, the more we can better manage our water for present and future generations.
Kelsey hopes to complete her research project, culminating with her master’s thesis in May. The paper is titled: Geospatial analysis of nitrogen hotspots from mushroom farming in the Brandywine-Christina River watershed.
You can learn more about how students and faculty in the University of Delaware's Geography Department are using geographic information systems (GIS) to solve environmental problems in this video featuring Kelsey.