Date of Award


Publication Type

Master Thesis

Degree Name



Earth and Environmental Sciences

First Advisor

Jianwen J.Y. Yang

Second Advisor

Tiequan T.Z. Zhang


APEX, Calibration and evaluation, Eutrophication, Lake Erie, Phosphorus




Modeling phosphorus (P) loss through surface runoff and subsurface drainage is essential because it helps understand how P transfers to the water bodies in an inexpensive and feasible way. P loss into the Great Lakes leads to eutrophication. APEX (Agriculture Policy/Environmental eXtender) is extended from EPIC (Environmental Policy Integrated Climate model) and can simulate management practices and land use impacts for various land sizes from a field to a small watershed. However, APEX has not been tested in Lake Erie Region. This research, therefore, represents the first effort to use APEX to simulate P loss in this area. Field data were obtained from experiments conducted at the Agriculture and Agri-Food Canada's Whelan experimental farm in Woodslee, ON, Canada, with corn-soybean rotation. Calibration and evaluation of APEX was executed to test its capability in simulating the impacts of chemical fertilizers and cattle manure on P loss. Different potential evapotranspiration equations (PET) and curve number (CN) equations were used to determine the most suitable one for this study area. Statistical analysis was used to assess the model performance. Satisfactory results were obtained from the simulation of APEX in the Brookstone clay loam soil.