What are the circles in Wichita county in Kansas?

Question

Go onto google earth and find kansas, wichita is a county on the far left. The whole county is covered in circular pattered fields... what are these for??

Answer 1

It comes from "circular pivot" irrigation.  Basically a long arm that is on wheels is attached at one end to a water supply.  It is then moved around the field (making a circle) watering the plants.  Photos below:

http://www.wtamu.edu/~crobinson/Irrigati...

http://picturethis.pnl.gov/im2/sprinkler...