Doc snapped this aerial photo from his window seat. It depicts “farms with center-fed irrigation, in the San Luis Valley of Colorado”. It immediately reminded me of a childhood game, Connect Four:
Speaking of flying, Doc recently posted a flight hacker’s guide, which travelers may find useful.
UPDATE: Thinking about this, did anybody else notice that they’re wasting a bunch of space for each circle-in-a-square? Roughly 22%, if I’m not incorrect. Mind you, water is surely a scarcer resource than land, so I’m sure the circles are a wiser approach. And maybe they grow some low-water crop in the extra 22%?
DarrenBarefoot.com 
Perhaps the corners could be left for native vegetation/wildlife. Although I realize thats idealistic & unlikely.
That does seem a little wasteful.
On a side note, the geek in me worked out the actual numbers and it’s closer to 21.5%.
Square area = 2 x 2 = 4
Circle area = pi x 1 = 3.14159…
4 – 3.14159… = 0.85841
0.85841/4 = 0.2146 = ~21.5%
Is it just me, or could they reduce that 21.46% by offsetting the rows and overlapping the uncultivated areas of the squares. But then again, the uncultivated areas between squares can be used for transporting machinery to each square. If they overlapped, that would result in crop damage when the farmers need to transport machinery to a square with no road access, which would be pretty much all of them.
It’s not uncommon to have edge row field breaks, even with center pivot irrigation. Here in Canada, there is even government support for development of wildlife habitats, in combination with erosion barriers and field breaks. See http://www4.agr.gc.ca/AAFC-AAC/display-afficher.do?id=1198864371354&lang=e.
(I was once a marketing assistant for Agriculture Canada and I had to research and write about this topic.)
I’m pretty sure there’s a servo-controlled end-of-pivot sprinkler design that can square up the circle, but apparently the cost/benefit doesn’t make it an obvious buy and install.
If you “fly” around, you can find places where (semi-)circles are offset to make a less wasteful fit, but ease of surveying and road-building (and driving a tractor) on a grid makes that the default pattern.
Actually, you can see some of the fields in Doc’s pictures have their corners irrigated, and the fallow corners greatly reduced. I’d guess the “hard circles” are on their gradual way out.
Thankyou for posting these pics, I was on google earth researching land when I saw the crop “circles”, I showed my husband because he has never seen them but I had quite a few times travel by plane. It was nice to show him something different that he would believe.
:0)