Liq N can be sprayed over top with good results, and as a bonus it boosts your turndown herbicide. Unless it rains fairly soon after application, stabilized N might be a good idea. My favorite way to apply N is pre, with another application, maybe 1/3 post, injected in the ground. It doesn't have to be deep, just an inch or two, but that keeps it where you want it. A simple coulter, with an injection nozzle behind is sufficient. My fertilizer supplier has a rental rig. Rent is only $1 if I get all my N through him. I apply 10-34-0 or similar through the planter, so I am not sure about the best way for the P & K.
