What did I see? Rings of green from an airplane...?

Question

Flew from Chicago To SF and it was clear, and I saw something, mostly over eastern Colorado, Utah, and South Dakota---they were growing crops in circles, sometimes there would be a half-dozen green circles (as seen from 30,000 feet) close together, sometimes more, sometimes just one or two---the circles sometimes varied in size, but they were obviously some sort of crop. What was I looking at?

Answer 1

Some areas use water plants to clean gray water before using it to irrigate. You may have seen the tanks with the plants on top.

Answer 2

an irrigation system.  water is pumped to a central base and through a pipe on top of a wheeled arm that rotates as the sprinkler heads irrigate, so there is a circular area watered

Answer 3

When you say crop circles i think Aliens but i doubt that's it.. My best guess would be an irrigation system it seems to be a more logical way of watering if you have a rotating sprinkler but then again it could be aliens you never know lol.....

Answer 4

Glenn T is right. It's easier in some areas to have a single rotating sprinkler than to plant crops the old fashioned way in furrows. Here's a different angle from-the-air view:

http://food.oregonstate.edu/images/water...

They were probably green because many crops in the summer haven't hit harvest and germination yet. But as you can see in this photo, sometimes the circles can get very busy and sometimes as they hit harvest time they turn "yellow":

http://img67.imageshack.us/img67/9648/cr...

Really odd is when the farmer doesn't have much land to work with and he plants multiple crops in one circle. They can then have a "pie chart" effect like this:

http://farm1.static.flickr.com/96/256403...

Anyway, hope this helps.

And if what you saw was not "circles" but "rings" from that height, they were more likely university or research built supercolliders than "alien circles." Hope you enjoyed the view, anyhow!