We do variable rate 80k-140k in 20" rows no tilled into corn stalks.    The majority of the acres are in the 110k-120k range.   Areas with white mold issues get less seed, light sandy ground gets more seed.    I would do exactly the same if we were in 15" rows.

We do plant 100% treated seed as I want the seed we plant to come up, I don't want to plant extra seed because I do not want a thicker stand if it all comes up.


My experience with crusting/replant decisions is that dropping another 20k seeds wouldn't usually change the decision as the decision to replant is usually made because of the stand having huge gaps in it.   When 0% of the seed emerges in an area, adding another 20k seeds x 0% emerged is still 0 viable seedlings.

Also, switching to 100% no till has greatly reduced crusting issues.