Too Much Fertilizer?

The latest issue of National Geographic contains an article called The Curse of Fertilizer.  It is a fairly well done article, but contains some simplifications that seem to me to be misleading.  Using and managing nitrogen fertilizer is one of the most complex things that farmers try to do.  I cannot say with certainty, but it appears that the writers believe that all the nitrogen fertilizer that is applied to the crop and not removed and eaten, is wasted.  The fate of that "excess nitrogen" is much more complicated than the article makes it appear.  Some of it is stored in plant remains both above and below the ground.  Some is returned to the atmosphere.  Some does enter both ground and surface water.

The article does feature some information about organic farming and a farmer who is trying to use a closed system where he uses livestock and legumes to add nitrogen to the system.  They add balance to the article by pointing out that yields are reduced and what he produces sells at a premium.  Another technology they mention is the use of cover crops.  I agree that long term use of cover crops has the potential to help us manage nitrogen more efficiently.  The problem is that the complexities of the nitrogen cycle makes nitrogen management into guess work even in a well managed system. 

If we can better predict weather on a long term basis we could utilize nitrogen fertilizer better.  Am I saying there is no hope to do a better job?  NO!  There are a number of tests that can be used to come up with a base level of nitrogen needed.  We use the Pre-Sidedress Nitrate test to help figure out how much nitrogen is remaining in the field at a certain time.  We can then make decision about adding more nitrogen.  There are mathematical models like this one developed by Daryl Starr that appear to have some utility.  Many are talking about split applications.  Green Seeker types of technology are another method to help mange nitrogen more efficiently. 

It is clear that better nitrogen management will help us grow more food at less cost.  The bonus is cleaner water and less energy consumption.