To quantify the agronomic performance and nitrous oxide (N2O) reduction potential of multiple enhanced efficiency nitrogen fertilizer technologies now available or soon to be marketed to farmers. Consistent with the 4R Nutrient Stewardship principles, the project will assess how changes in fertilizer application timing (spring versus fall) and nitrogen source (urea versus anhydrous ammonia) can be stacked with new technologies to stabilize soil nitrogen, enhance crop yields and prevent unintended losses of nitrogen from the soil.