ADVANCING KNOWLEDGE AND PREDICTION OF PHOSPHORUS DYNAMICS IN TILE DRAINED LANDSCAPES

Our long-term goal is to provide science-based information to farmers and other stakeholder groups to support sustainable agricultural production while promoting water quality. The principal goal of this project is to improve our understanding of phosphorus (P)loss in tile drainage systems and improve tile P simulation in an existing nutrient transport model. Our central hypothesis is that the ratio and time of soil-water contact will dramatically impact P losses, and that this dynamic between hydrology and soil P will dictate the ability of a soil to behave as a sink or source of P. The following objectives will test this hypothesis:Quantify how dissolved P (DP) transport in tile-drained fields is impacted by soil properties and hydrology.Improve simulation of macropore and matrix P contributions to tile drainage and P dynamics in the soil matrix in the Soil Water Assessment Tool (SWAT) model.Evaluate SWAT model improvements by comparing the simulated tile DP and total P (TP) outputs against edge-of-field monitoring data.