This is from a few weeks back when we were looking at compaction issues on a farm. It is so fun to work learn and visit with farmers who get as excited as I do to see worms in the field. #agriculture #soilscience
That can be an answer. This farm started as a cattle ranch and they integrate livestock, but they are still struggling with some bad compaction. Conversely, I have seen going from tillage to pesticide dependent no-till even without animals result in an increase of earthworms.
It has mostly to do with iron oxides in the soil. I believe the clay adheres to the iron oxides helping it to keep the red appearance. Oxisols found in highly weathered environments can be much more red.