Thanks for the pics.  however I don't understand the overall project:

" Took these pictures in a pit we dug on the headland of some radishes we planted the middle of August into 120bpa corn residue."

Your location says WC IL. Was this corn the previous year then wheat harvested in July and radishes planted in Aug?  Year old corn residue that nothing else was planted into this spring?  Was this August harvested silage corn (not much residue)?

Or was this a super early hybrid harvested in August due to the drought?

One of the issues with cover crops in northern corn growing areas is that it is tough to get a stand of anything planting after a normal corn harvest in Sept and Oct.  The radishes seem to work best when planted after summer harvested wheat, which there is not much of in corn country these days.

Trying to learn something new here.  Thank you.

Jim at Dawn