Nebraska is increasingly facing significant nitrogen (N) management challenges in sustaining corn production while protecting drinking groundwater quality. One option to address these challenges is to follow the “4Rs” concept (the Right source, at the Right place, in the Right time and at the Right rate). Results of this study will be used to improve UNL’s nitrogen algorithm and provide much-needed information to stakeholders in identifying the Right fertilizer source and Right placement at the Right timing of N application for sustaining crop yield, improving profits, reducing N losses and protecting water quality.