I think that 2nd pic looks intriguing.  I'm also wondering why the beans look better in the wheel tracks.  Have you dug up any plants and looked at the roots? I am wondering if the plants in the wheel tracks have longer, deeper roots compared to the ones not in the wheel tracks.  IF that is the case, did compacting the soil give a better environment for the roots to grow? Is the compacted soil less water-logged?   I don't know - I'm only guessing ........