.

Regarding this, why are some fields circular?

Because the water falls directly on the crops instead of being shot into the air as occurs with traditional sprinklers, less water is lost to evaporation and more goes to nourishing the growing plants. Central pivot irrigation also creates perfectly circular fields, as seen in this image.

Additionally, what are the round circles on the ground? Dicum told io9 that the landscape people find most mysterious is "big round green circles in the middle of [North America]." (You can see an example in the image above.) So what are those weird circles, anyway? "It's called pivot irrigation," he said. Essentially they are farmlands.

Similarly, why are there circular fields in Colorado?

Center-pivot irrigation was invented in 1940 by farmer Frank Zybach, who lived in Strasburg, Colorado. It is recognized as an effective method to improve water distribution to fields. The early designs were finicky and few farmers understood the systems.

What are the circular fields in Kansas?

This NASA's Landsat 8 satellite image, acquired on July 6, 2014, shows circular fields in Kansas, USA. This method, also called waterwheel or center-pivot irrigation, is a crop irrigation in which equipment rotates around a pivot and crops are watered with sprinklers.