We're always looking for ways to consume less resources per acre. Most of our nitrogen comes from the old fashioned source - shit. We use some dry urea and anhydrous ammonia as well, but the goal with nitrogen application is to get it into the plant and avoid or minimize any extra release into the atmosphere.
A lot of the bad rap farmers get for nitrogen run-off comes from large livestock integrators who are either not involved in crop production, or only raise crops as a means to dispense of manure. Because they have more manure than land they can responsibly fertilize with it, they tend to over apply, and create the bulk of the nitrogen related issues seen in intensely row-cropped areas.
An operation like ours has more farmland than manure, so we can apply the manure we do have in a timely fashion, and an appropriate amount of ground. This helps ensure that the soil absorbs the nitrogen and stores it through the winter to apply to the seed/plant in the spring. A lot of our land will never get manure, and on those farms we either apply anhydrous in the fall, or dry urea in the spring and growing season. Again, all of this is done to maximize absorption by the corn plant and minimize evaporation or run off.
At the end of the day, the guys raising corn for ethanol want to capture as much nitrogen as possible and let as little as possible evaporate into the atmosphere or run off into the water system. Because they get more money for growing more corn. The guys raising corn because they need to get shit out of their stock yards or barns are less concerned with this, generally, because they get paid by selling more cows and pigs.