Often when I am travelling I see these giant green circles on the ground. They look beautiful and is clear are man made. But what is going on. I have seen them all over the US, on the west coast, while flying to east or south you can see them.
Finally the mystery was solved when I was watching “America Revealed – Food Machine” by PBS. These are agriculture fields or food factories irriagated by something called central pivot irrigation system. Here is a difintion from wikipedia
Central pivot irrigation is a form of overhead (sprinkler) irrigation consisting of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. The machine moves in a circular pattern and is fed with water from the pivot point at the center of the circle.
If you have an hour to spare the PBS documentary is a great watch. You will be amazed at the scale, efficiency, diversity of this giant food producing system. Some of the scenes are quite haunting like all cows getting lined up for getting processed as beef or the host of the show looking in the eyes of a cow and saying is this the same animal or something man made etc. Description of the episode from PBS
Over the past century, an American industrial revolution has given rise to the biggest, most productive food machine the world has ever known.
In this episode, host Yul Kwon explores how this machine feeds nearly 300 million Americans every day. He discovers engineering marvels we’ve created by putting nature to work and takes a look at the costs of our insatiable appetite on our health and environment.
For the first time in human history, less than 2% of the population can feed the other 98%. Yul embarks on a trip that begins with a pizza delivery route in New York City then goes across country to California’s Central Valley, where nearly 50% of America’s fruits, nuts and vegetables are grown and skydives into the heartland for an aerial look of our farmlands.
He meets the men and women who keep us fed 365 days a year—everyone from industrial to urban farmers, crop dusting pilots to long distance bee truckers, modern day cowboys to the pizza deliveryman.