US farmers were impressed by the UK "UFO Crop Circles" and, being
inventive types, figured out a way to make circles automatically thus
leaving them with time to go to tractor races.

Seriously, it's an irrigation system with a well at the center and a
rotating sprinkler pipe up to half a mile long. An irrigated circle
produces more crop than a square relying on rainfall. It's probably a
transient phenomena given the rate at which aquifers are being
depleted.

Dalhart, TX area corn farmers were turning off the outside sprinklers last summer in an attempt to save the inside of the circle. Even the irrigation couldn't keep up with the dry heat.

Low Aquifers are definitely a problem for farmers, espeically when those states upstream (cough cough wink wink) take all the water!