Developing a Mathematical Model for Plant Interaction in the Nitrogen Budget of Small Watersheds

Over the past summers Richard Bernatz and Luther College students have developed a rainfallrunoff model for the Upper Iowa River watershed. This model simulates the water flow within the subcatchment and is able to estimate the outflow from the mouth of the subcatchment. The current research involved updating the existing model as well as developing and incorporating a new model for simulating processes of the nitrogen cycle, including plant interaction, denitrification, nitrification, and leaching. The goal of the research was to be able to estimate the amount and concentration of nitrates flowing from a subcatchment of the Upper Iowa River under various circumstances.