This year I have obtained a water soluble syphon mixer. It fits on a standard garden hose and one end is placed in a fertilizer concentrate which it then syphons into the hose at a set rate. All one has to do is mix the fertilizer to the proper concentration and once it is all syphoned out your done. Sounds pretty good but I'll probably try it out on something else first to see it it is syphoning at the correct rate, wouldn't want to over or under fertilize. I don't know if it could be adapted to a presurized sprinkler system but I'll planing on using it on my rain tower and soaker hose.It usually costs about 10-15 bucks and its made by Hyponex John