All we put down around here is NH₃ for our hard red winter wheat.  I finished putting down the NH3 a couple of weeks ago, and we usually sew the wheat around the 15^th-20^th of Sept., depending on rainfall during that time frame...  Around here, we usually put down about 50# of N (we're talking about dryland, here); and we usually come in with pretty good yields (all the wheat around here gets grazed, too).  We all know that moisture has more to do with it than anything....This year, we averaged in the 70's (BPA).  If it is looking like it is going to be a good year, I will pull soil samples in the spring, and top-dress with Urea if necessary.

Personally, I 'plow' the NH₃ in; meaning I have a NH₃ setup on my JD 1610 chisel plow.  Every shank on the back row has a NH₃tube on it (a tube along side each wing of a 18" sweep), and one or two (total) on the front rows of shanks.  I don't know for sure, but I would guess the spacing of the fertilizer to be about 24".  Just about everyone I know around here has a very simular, or the same set-up.  I use JD 9300 or 9400 hoe drills, 10 or 12" spacing...we sew about 35 lbs/acre of wheat.