Hydraulic Effects Of Crop Management Systems On Nitrate Variabioitiy In a Confined Aquifer.

Cropping systems and soil management practices effect solute movement through a saturated argillaceous till aquitard (~6 m thick) to a shallow confined aquifer, not only through efficiencies of nitrate consumption, but through separate and distinct hydraulic effects on surficial water movement, the subsequent distribution of infiltration, and the resulting distribution of localized water-table mound formation, which moves post-storm surges of solute from the overlying aquitard to the upper aquifer. Hydraulic effects of cropping systems can significantly impact the spatial and temporal distribution of nitrate measurements in the upper aquifer, even on apparently level landscapes. Understanding of hydraulic effects is important for evaluating nitrate concentrations and dissipation rates in aquifers underlying cropped fields following storms.