It some what depends on soil type and moisture.  We work the ground, apply NH3 and then work it again all it the same hour or what ever the field size is.  Some years on heavier clay we would get some noticeable root injury if it was a little damper.  Last year we added another autosteer with corrected signal (Centerpoint rtx).  Then we shared the same lines with the planter monitor and  the nh3 tractor.  Then we off set it to run in between rows, even though we can't see them.  Worked great!