The species Elaeagnus umbellate, more commonly known as autumn olive, is a shrub that is invasive to the United States and indigenous to East Asia. Even though the autumn olive is not native to North America, it was able to thrive and adapt to the new environment by using its ability to fix nitrogen. Nitrogen-fixing is a process where plants intake molecular nitrogen from the atmosphere and convert it into other forms of nitrogen that can be used by the plants. One of the nitrogen-fixing by-products is nitrate. Excessive amounts of nitrate can easily leach from the plant’s root region into underlying aquifer systems. Relatively small amounts (>10mg/L) of nitrate in the environment are known to be toxic to humans and aquatic life. This study was conducted to assess the impact of Elaeagnus umbellate on nitrate concentrations in its surrounding soil and groundwater. Thirty plots were selected for collecting groundwater and soil samples. Fifteen of those plots were dominated by mature E. umbellate. The other fifteen plots were dominated by native grass species. Water and soil samples were collected two feet below the ground surface (root zones of the autumn olive plants). Samples were collected during the growing season, in ten day intervals during the summer of 2010, and analyzed for the respective concentrations of nitrate, ammonia, total nitrogen, potassium, calcium, and magnesium. The data obtained from these analyses was statistically analyzed. The results of the samples collected from the autumn olive dominated plots showed an increase in the concentrations of nitrates and other nitrogen forms. However, statistical t-tests showed that this increase is not significantly different compared to results of the control plots dominated by native grass species.
Aljobeh, Yacoub and Engerer, Kristin, "Impacts of the Species Elaeagnus umbellate on the Soil and Water Quality of the Pierce Cedar Creek Institute Ecosystem" (2011). Symposium on Undergraduate Research and Creative Expression (SOURCE). 11.