If I could bypass fertilizer all together I would but I have found that two 50lb-60lb dogs damage and stress out the lawn with all of their running around, especially in the rainy months. In my endeavor to strive to be more environmentally friendly I began using low nitrogen organic fertilizers four years ago.
I have had mixed results with organic products. One of these organic products caused six inch mushrooms to grow every night for a couple of weeks giving the dogs a potentially poisonous treat. Picking mushrooms at 5 am so the dogs do not eat them is not a treat for the humans!
This year I decided to switch to a liquid organic hydrolyzed fish solubles fertilizer and kelp. Due to the fish oil in the fertilizer the yard has a bit of a fish odor. Fortunately the odor is slowly diminishing. For the next application I will definitely use gloves - I have washed my hands multiple times but some fish oil odor still is present.
It it not for everyone but I do recommend composting, organic fertilizer, rain barrels, etc. It does take more time but I believe it is less taxing on the environment.... well at least to me!