Talk:Center-pivot irrigation

So, in rural areas, 3 phase power is not readily available and as the case, 3 phase has to be generated. Traditionally, this was achieved with a phase converter that would take single phase as an input and provide 3 phase power as an output. Within the next two weeks we will be retrofitting a 30 old center pivot system with 2 Horse Power VFD's on each tower that can take single phase input and will provide 3 phase output for each individual motor at each tower. I don't know if anyone has done this yet but I believe it will be revolutionary on multiple levels. First of all accomodating what power is available for the user, providing a soft/gentle start to the motor and gearbox in general which should extend the life of the gear boxes and tires. If this were to be incorporated into a new center pivot, the amount of money in wire and other hardware would be significantly reduced. A savings for the manufacturer and the end user. — Preceding unsigned comment added by 50.30.16.41 (talk) 04:00, 10 April 2016 (UTC)

Rationale

As a layman knowing nothing of agriculture, it would be interesting to see more elaboration on why these center pivot machines are used rather than a square layout given the waste of space. —Preceding unsigned comment added by 68.122.80.126 (talk) 07:04, 3 February 2011 (UTC)

A pivot system runs automatically thus saves on expensive labor to move pipes. With the drop type heads applying water close to or amongst the crops they save on water use. Bizzybody (talk) 19:03, 26 July 2011 (UTC)

Geometry of planting

I came here to find this out and was surprised that it's not mentioned: Are center-pivot fields planted (and harvested) spirally or concentrically? It seems to me that a spiral pattern would make the job easier, but a fair amount of Googling has left me none the wiser. —HorsePunchKid→龜 15:48, 2 June 2006 (UTC)

In my experience in central Washington, seedbed prep normally eliminates the wheeltracks. Crops rows are typically oriented according to drainage needs. The CP wheel tracks run right over the planted rows.

An issue with CP is that the instantaneous application rate on the perimeter can be higher than the infiltration rate because it whips along so fast, even with our sandy soils. Concentric rows, where the exterior row always gets the highest instantaneous application, could concentrate runoff and exacerbate ponding and erosion problems.

In one grass sprayfield (doesn't have ridged planting rows) where the wheeltracks have been filled with gravel, it was planted concentrically. Before they filled in the tracks they harvested the most rutted portions concentically. I haven't seen a spiral harvest, but I expect different farmers try different approaches. -- Paleorthid 16:21, 2 June 2006 (UTC) > revised 28 June 2010.

Strange question that got me thinking: the irrigation system produces circles, and yet they're still arranged on a square grid instead of a triangular or hexagonal one (imagine honeycomb and you'll see what I'm getting at). That leaves the corners of each square grid either left fallow or less-efficiently irrigated. Was any research ever done into stacking them this way for better yields? --The Centipede 17:51, 12 August 2006 (UTC)

If you follow to Irrigation in Saudi Arabia, you'll see a picture showing (some) honeycomb arrangement. It seems that in America, central pivot irrigation has been retrofitted onto traditional square fields, with no change in crop layout. Yet

the apparently more recently developed Saudi agriculture tends to have been laid out with consideration given to central pivot irrigation. I presume that has something to do with it; if your farm predates central pivot irrigation, you tend to go with square arrangement; otherwise you plan for maximal use of space. Refitting into square plots (without sub-plots) wastes 21% of space; fitting into hexagonal plots only 8.5%. Seems like it would be an interesting subject. - Keith D. Tyler ¶ (AMA) 20:05, 13 October 2006 (UTC)

That should be mentioned in the Saudi article. Only some of them seem to be in honeycomb arrangement. 141.155.28.92 01:01, 14 October 2006 (UTC)

A corner attachment extends and retracts to reach the corners, the corner attachment is a large expense relative to the rest of the pivot and the farmer has to weigh the cost to the return. Sigrud ds (talk) 00:47, 12 January 2012 (UTC)

Translation

Is it allowed to translate texts on wikipedia direct into another languages? —The preceding unsigned comment was added by 62.47.140.108 (talk) 15:06, 18 February 2007 (UTC).

A.f.a.I.k. yes, but do not forget to credit the source, e.g. the english version of wikipedia. VanBurenen 13:24, 18 March 2007 (UTC)

Measurements

Does someone know some data that quantify such an irrigation system? E.g. typical, average, even record length of array (how many yards or meters?). Quantity of water pumped. Speed of rotation, etc. VanBurenen 13:24, 18 March 2007 (UTC)

Co-ordinating Motors

Since the wheels at the outer edge of a circle must travel a greater distance than the inner wheels in a given amount of time, how are wheels and sprinkler heads kept in a staight line from the center to the circumference? - John V (23:12, 1 July 2007 74.36.100.241)

The percent timer in the center control box tells the last tower of the system what percentage of the time it is supposed to move. All other towers move relative to that last tower. On a Reinke system, at the top of the tower where two spans connect, there is an electrical control box. On either side of the water pipe are two alignment rods that are held against a bracket by spring tension. The bracket itself is connected to a microswitch inside the control box. When next tower further out moves forward, this causes the microswitch to engage because of the slight rotation of the bracket that is connected to it. This causes the tower to move forward until the angle is straight enough to disengage the microswitch and stop the tower from moving. You can adjust the angle at which you want the tower to being moving by adjusting two alignment screws on the bracket. If the towers get too far out of alignment (due to getting stuck or for any number of reasons), that same microswitch has a safety that will shut down the entire system. Most electrically-driven pivots have a similar alignment system. -68.226.72.4 14:05, 12 July 2007 (UTC)

Does it call out when it needs service or have a flashing service light? I can't imagine that these systems can be unattended for more than a couple of days if they need service since you could start losing crops. 67.67.9.55 (talk) 17:52, 14 May 2010 (UTC)

Urapivot.jpg

The photo at Urapivot.jpg, subtitled "Center Pivot Urapivot made in Spain" is pretty shitty. It is blurry and stuff. I suggest we remove it cause of the quality. Plus it is in like a gallery of other photos, not add much on its own, ya know?

Let me know whacha think-Peter Napkin Dance Party (talk) 00:31, 3 February 2009 (UTC)

WHy the complaint/flag about sourcing

And why threaten removing content. This article is interesting, an was clearly written by people with practical knowledge. Sure, we can add some content and citations, but this sort of practical knowledge does not show up much in textbooks, and for millions of people who work in agriculture, is as basic as saying that Toyota and Nissan are major car manufacturers. Let's not be petty and triggerhappy in flagging. Wxidea (talk) 17:07, 8 October 2010 (UTC)

This is a common tag for noting articles that need additional sources. While the article as written today may be correct, the policies at Verifiability and Citation strongly encourage sources to be identified to avoid problems with original research. So far there haven't been any challenges here, but some articles (cow tipping) have tons of problems with people putting in material that is urban legend or just plain wrong. The tag isn't a threat, (though it does read a little harsh and I wish the wiki-gods could maybe tone it down a bit) it's a tag to encourage those who care to do a little more work to improve the article. Montanabw^(talk) 22:42, 9 October 2010 (UTC)

I would agree that the sources can change but some have been a source for at least 80 years and should be listed for historical reasons and are well known in the agriculture industry. However source percentages are always changing and I believe to be irrelevant to the article. The source percentages listed I believe to be inaccurate as one major source that has been doing so for over 80 years, Pierce Corporation, is not yet listed in the article at this posting.Sigrud ds (talk) 23:25, 11 January 2012 (UTC)

Newer developments.

Originally, these systems mounted impact "gun" type sprinklers on top of the pipe. The ones with the U pipes hanging sprinkler heads low are conversions of existing systems or of old inventory prior to sale. New systems hang the sprinklers from the bottom of the pipe. The newest development is a double pivot with a swinging end section that has steerable wheels. As the main pipe swings around a corner the end section straightens to reach the field corner. The wheels steer to keep the end of the line following the edge. This eliminates the dead corners problem. Bizzybody (talk) 19:14, 26 July 2011 (UTC)

Linear systems.

While *automatic* linear systems are uncommon, manual or semi-automatic ones are very common. With a manual type, the irrigator must go to the field, disconnect the feed pipe, run the motor to roll the line forward then reconnect the pipe. A semi-automatic type uses a large hose to allow the line to roll further between having to move the water connection. They can also be manually advanced. Bizzybody (talk) 19:20, 26 July 2011 (UTC)

The *automatic* linear systems use a ditch or canal feed where the hose is pulled along while submerged and does not need to be changed; a fairly common practice in New Zealand and middle eastern countries. Sigrud ds (talk) 23:07, 11 January 2012 (UTC)

Sector Irrigation

Many of these CP systems now irrigate less than the full 360 degrees. Often a half circle, or a quarter, sometimes some other angle. I assume they automatically reverse, like a car windscreen wiper. When did this technique start? Are there different ways of doing it? 86.149.93.32 (talk) 04:38, 13 January 2014 (UTC)

Date of Invention

Please check the source regarding the invention date - this article says 1940, but various online sources (see http://www.livinghistoryfarm.org/farminginthe40s/water_09.html) indicate that Zybach didn't start working on it until 1947, and didn't get a patent until 1952. I suspect a typo, but perhaps that book somehow has better information.

--HistorianK (talk) 00:19, 24 August 2015 (UTC)

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Speed/time

How long does a typical 1/4 mile center pivot take to complete a full rotation? Or putting it another way, what speed does the outer edge of the wheeled structure typically move at? Beorhtwulf (talk) 10:50, 14 April 2020 (UTC)

Slowly. 2-3m (6.6-10 feet) per minute. [1].PrisonerB (talk) 11:09, 14 April 2020 (UTC)

Thanks. So I make that 2*pi*400m/{2or3m}/60mins= 14-21 hours for a full rotation of a 1/4 mile radius set-up. Beorhtwulf (talk) 09:59, 21 April 2020 (UTC)

It doesn't need to go any faster, watering once a day is more than enough usually.PrisonerB (talk) 11:06, 24 April 2020 (UTC)

Geoography

Article is very US-centric, doesn't really say where else this system is used (except Saudi Arabia) or if not why not. Anyone know? 80.189.247.175 (talk) 13:11, 9 July 2022 (UTC)