As easy as pvc is to deal with, we always built a manifold the length of whatever implement it was going on (planter or applicator).  Put a hole at each row with a nozzle body that has a orifice inside of it and air line back to the row.  Used 1/4" tube on popup/in-row stuff and use 3/8 on the applicator.  So, is it necessary, I don't know but I always liked that approach vs running 30' of hose with a 1000 zip ties.  To each their own.