It doesn't look like the green beans are caused by something as much as the not so lush beans are caused by something.

The chunks of limestone on the surface where your 4 wheeler is parked is a big clue.  All the beans that don't look as good as the green streeks most likely have varying amounts of free-lime exposure.  Your green streeks have the least damage from the excessive freelime IMHO.

If you could travel back in time and see the topography prior to farming, it would reveal the reasons for the streaks I believe.

Planting Iron Chlorisis tolorant varieties helps, so does rain....