[HN Gopher] The Unexpected Elegance of Irrigation Systems from A...
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The Unexpected Elegance of Irrigation Systems from Above
Author : pseudolus
Score : 61 points
Date : 2020-08-30 10:45 UTC (12 hours ago)
(HTM) web link (www.atlasobscura.com)
(TXT) w3m dump (www.atlasobscura.com)
| anotheryou wrote:
| They easily could win 10% area usage by packing better.
| http://www.datagenetics.com/blog/june32014/index.html
| azepoi wrote:
| Square packing density is pi/4 (~78.54%). The non regular
| packing approaches a hexagonal packing (pi*sqrt(3)/6 =~ 90.69%)
| for large N. For N=120 for example d=85% http://hydra.nat.uni-
| magdeburg.de/packing/csq/csq120.html
|
| Does not seem practical in reality (39 or more systems instead
| of one). Maybe for extremely vast fields where you would have
| many systems anyway.
| hinkley wrote:
| What the circle packing does accomplish though is to collect
| more of the uncovered space into semi-rectangular areas at the
| edge of the plot, which could be used for other purposes, like
| buildings or specialty crops. The plumbing is more complex
| though. One circle is one pipe, 1/2 of the width (sqrt(2)/2
| diagonal) Four circles is at least two pipes, 2 width or more
| and, you might have to run the irrigation sequentially due to
| flow rate. That could mean time in the field.
|
| I was watching a Joel Salatin video recently and he was
| pressing the point of having irrigation and other systems where
| you don't have to cross the property, on foot or with
| equipment, to do chores. It's a huge time sink and some days
| you will run out of time. If you have to stay for the duration
| it's even worse.
| jackfoxy wrote:
| Good thought. The practical barriers to better packing are
| access roads/tracks and property lines. Both of which tend to
| be straight.
| cortesoft wrote:
| Sure, if the only limiting factor was space. It is likely that
| the cost of being more efficient with space usage is not worth
| the extra costs.
| neckardt wrote:
| While true in theory, this doesn't hold up in practice.
|
| The farmers here are constrained in space by roads on all sides
| and by the price of each irrigation machine. Many small
| circular irrigation machines will be more expensive and harder
| to maintain than one large one.
|
| The article you linked shows how given a square area, the
| packing efficiency of a non-square packing order increases past
| 80% only after you have around 30 circles and even then the
| increase is negligible. It would take well over 100 circles to
| hit the 10% additional area usage you're talking about.
|
| For farmers who want to make use of those corners of their
| field just use an irrigation system which can handle corners
| and make 100% use of their land.
| darkerside wrote:
| Makes sense. Land is so cheap out there, that's the last
| place to be optimizing your trade offs.
| azepoi wrote:
| This is only true if the circles are all of equal radius.
| With only 5 circles and 2 sizes you can get a significant
| increase to 87%. But the problem of practicality and cost
| benefit still stands.
| WJW wrote:
| There are these type of linear irrigation devices that will
| cover square/rectangular fields more completely:
| https://www.valleyirrigation.com/linears . In practice I
| don't think super optimal land use is very critical for most
| farmers though, when compared to the additional cost for
| acquiring and maintaining more complex irrigators.
| neckardt wrote:
| I initially thought the use of circular irrigation devices
| would be when land is cheap, but after some research I
| think the main reason to use them is when water is far more
| expensive than land.
|
| I zoomed in to various areas in the Midwest US, and I
| didn't see a single use of the circular devices, only
| square fields which are likely using the linear irrigation
| device you described.
|
| However, in areas where water is more expensive such as
| Colorado, I see the opposite: Only circular irrigation
| devices.
|
| I think what's happening here is that circular devices
| shoot the water down which causes all of it to land on the
| crops. The farms in my area generally use a firehose style
| sprinkler which shoots the water up. This causes a large
| chunk of water to get lost but it hits the corners of the
| land. Due to the cheaper water costs in the midwest, this
| is acceptable.
| icegreentea2 wrote:
| My understanding is that many farms in the midwest (as
| least corn farms) don't irrigate - rainfall is
| sufficient.
|
| Linear and circular systems should in principle be able
| to achieve the same water efficiency (within their swept
| area). They're the same thing - an above ground wheeled
| mechanism to deposit water.
|
| If you're farming in an area where you're water
| constrained, then you might not necessarily care about
| parts of your field not being used (as long as it's
| reasonably small), since what you care about is your
| input to output cost.
|
| Some advantages of central pivot is that: a) you only
| need to feed water to a single fixed point - in a linear
| system you either need a ditch to draw out of (that's
| water loss right there), or drag a hose around (that's a
| possible point of failure) b) you don't need to figure
| out how to regulate the two ends of your line to keep
| them in line.
| maxerickson wrote:
| Lots of land in Michigan isn't irrigated at all. So that
| may be some of the difference you are seeing in the
| Midwest.
|
| https://www.usgs.gov/mission-areas/water-
| resources/science/i... has a coarse map indicating a
| significant difference in practices.
| dugmartin wrote:
| The only irrigated fields I know of in the Midwest are
| for water hungry crops like melon (my background; I grew
| up in the Midwest, I'm the first generation on both sides
| of my family not to grow up on a farm, I spent most of my
| summers on the farm where my mom grew up)
| contingencies wrote:
| If water cost is the key concern then surely alternate
| technologies such as drip-lines, inter-cropping,
| greenhouses/poly-tunnels, windbreaks and mulch could be
| explored? Also, selecting less water-intensive crop
| varieties. Fundamentally, spraying water through the air
| is a great way to lose a lot of it, both in transit and
| in evaporation thereafter.
| AlotOfReading wrote:
| Industrial farmers are a bit trapped in what they can
| sell and how they produce it. They generally can't change
| varieties much because the plants they're producing are
| what the factory wants, and anything outside that
| expectation will sell for significantly less. Secondly,
| industrial crop fields tend to be hyper optimized towards
| using harvesters, which don't easily permit intercropping
| or things in the field to get tangled. Windbreaks in the
| form of trees are already common in many areas.
| contingencies wrote:
| All good points, but kinda tangential. To summarize,
| perhaps we can agree that there are opportunities for
| technology to make a substantial difference in the
| resource efficiency of agriculture, but there remain
| significant factors effecting inertia and lock-in to
| existing 20th century industrial agricultural processes
| which must first be overcome.
| Animats wrote:
| Hexagonal grids of round farms are found in areas such as Saudi
| Arabia which don't have a dense road network or rectangular
| land ownership.
| gdubs wrote:
| These would make great paintings, for sure. I'd hang a big one in
| the house.
|
| The original Cosmos had a great episode on life at different
| scales, and the magnitude you'd have to view earth at to so see
| evidence of life.
|
| Before that, there were the Eames with their great "Powers of
| Ten" film.
| centerpivot wrote:
| No reason to make it into a painting. Photos of this kind of
| thing can be art in their own right. I mean, who cares, but
| it's worth being aware that large photographic prints are
| acceptable as art, and, actually, photorealistic painting is
| often considered pretty cheesy.
|
| Here's an example of a photographer whose (troubling?) work
| takes the form of very large aerial photos of feedlots:
| https://mishkahenner.com/Feedlots
| gdubs wrote:
| Don't have to convince me -- I see photos as art too. I
| thought paintings with these because of the abstract shapes.
| So, not really photo-realism, but interesting compositions to
| lay down paint within.
| tesseract wrote:
| Somewhat relatedly, "The Jefferson Grid" Instagram account:
| https://www.bloomberg.com/news/articles/2015-09-16/the-jeffe...
| hallman76 wrote:
| Also somewhat related https://twitter.com/americasquared, which
| I think I found here on HN.
| badhabit wrote:
| can you vary the pressure of sprinklers? like max pressure on
| corners that a perfect square irrigation can be obtained.
| zdw wrote:
| Most of the time the rows are circular the irrigation system is
| a moving structure that rotates around the central point, where
| water is pumped into the system, then drops down on the crops.
|
| They frequently do have a sprayer at the end, but it's not
| sufficient to cover more than an extra few rows around the
| corners.
| centerpivot wrote:
| These circular areas are created by a rotating structure
| (https://en.wikipedia.org/wiki/Center_pivot_irrigation) not one
| sprinkler in the center of the field.
|
| The machines often have a radius of 400m, so they're a _lot_
| bigger than the range even a firehose could achieve.
| hinkley wrote:
| Some people refer to the rotating structure as "the
| sprinkler", but at any rate the question has some merit.
|
| Generally the middle of the structure has small sprayers
| evenly spaced, and the end of the structure has what looks
| like a regular sprinkler on steroids. The large throw
| increases the effective diameter.
|
| It's a fair question, but the net would be that you use a
| slightly longer structure and get a rounded rectangle, where
| the rounded rectangle is just a truncated circle of the area
| the same sprinkler could cover in theory. Weigh that against
| the yield and extra maintenance costs.
|
| I haven't seen this many times, but the Wikipedia article
| points out there are linear systems that irrigate rectangular
| areas. They use a canal on one end and pumps on the rig. That
| explains an unanswered question about irrigation practices
| I've seen in Eastern Washington.
| type_enthusiast wrote:
| Something that might be cool, if impractical: devise a system of
| end-to-end linked pivot sprinklers in a Fourier series that draws
| something interesting in vegetation when seen from above!
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(page generated 2020-08-30 23:00 UTC)