Since when did farmers grow circular crops?

August 9, 2006 3:13 PM

These are not crop circles, they are circular crops in south-western Alberta. What's the advantage over rectangular fields?

I was speculating about some kind of technology that would make circles efficient to water, but I'd love it if anyone with an inside scoop knew what was really going on.

posted by louigi to Grab Bag (11 answers total)

I believe it's the sprinkler pattern.

Where land is cheap, it costs more money to build sprinkler irrigation systems that have a mobile pumping system and/or a set of hoses that it drags along as it's spraying than the crops they'd get from that land is worth. The circle pattern allows them to use sprinklers with one central point.
posted by SpecialK at 3:15 PM on August 9, 2006

The watering system is easier to implement if it can pivot (pivet?) around a central point. I think fertilizer and such is fed through the same system. The loss of arable land is miniscule compared to the cost savings from the watering system.
posted by geoff. at 3:16 PM on August 9, 2006

Best answer: Probably center pivot irrigation. Highly common in the U.S. too! You can see those circular fields (or just of lively growth within a conventional square field) very clearly from the sky
posted by nelleish at 3:16 PM on August 9, 2006

Response by poster: Thanks, that's the term I was after, nelleish. I'm impressed -- if the Google Maps legend is correct then some of those circles are up to two kilometers across! Quite the irrigation system...
posted by louigi at 3:35 PM on August 9, 2006

I remember wondering about this when I was flying accross the US a couple of years ago and saw the circles.

Incidentally, it's unfortunate that agricultural land in the US and Canada is divided into a square grid pattern. It would be much more efficient for centre pivot irrigation if a hexagonal grid were used instead (as is done in some other parts of the world). Much less space is wasted that way.
posted by Emanuel at 4:18 PM on August 9, 2006

The old hydraulic CPI systems couldn't be stopped for love or money. That is to say, you always wanted to be careful not to leave your pickup in the path of one for a long period of time.
posted by autojack at 4:34 PM on August 9, 2006

It would be much more efficient for centre pivot irrigation if a hexagonal grid were used instead

It's only 78.5% vs 86.6%, and you'd have to drive in zigzags to get from one side to the other.
posted by cillit bang at 4:38 PM on August 9, 2006 [1 favorite]

It would be much more efficient for centre pivot irrigation if a hexagonal grid were used instead

It's only 78.5% vs 86.6%, and you'd have to drive in zigzags to get from one side to the other.

While that's true, I know I've seen hexagonal fields watered using CPI. Sorry, I don't know where precisely, just in the middle of the US somewhere (as I was flying over it). As I recall, each field was only a few hexagons, so the annoyance factor was probably small enough that it was worth doing.
posted by blm at 7:40 PM on August 9, 2006

This book is on its way to me this week as a requested birthday gift; you might also find it interesting, at the very least to peruse online:

Infrastructure: A Field Guide to the Industrial Landscape
posted by intermod at 7:46 PM on August 9, 2006

If you plow a field in a circular pattern, there's less wind erosion of the soil.
posted by Steven C. Den Beste at 10:09 PM on August 9, 2006

Or more.
posted by flabdablet at 1:46 AM on August 10, 2006