Could be areas where portable (chicken/turkey) pens were moved around a pasture after crops have been cut/bailed (hince"Range Fed")added-20/30% to egg market value.
Poultry ate the stubble/insects/airated & fertalized the ground.Could be the same for portable pens for lambs/expensive genetic-bred live stock??
Last but not least: Sat.-nite cowboy tangled up in his weedeater