Editing Center-pivot irrigation (section)

==History==
On March 23, 1914 James A. Norton of Odebolt, Iowa, filed the patent for the center pivot irrigation system. On August 17, 1915, it was granted as patent #1150144.  The patent drawings shows multiple pairs of wheels supporting a pipe that is moved in a circle around a center pivot point.  The description is:  Watering arrangements making use of movable installations on wheels or the like movable around a pivot centre.

Center-pivot irrigation was invented in 1940<ref name="Morgan 1993 35–36">{{cite book|last=Morgan|first=Robert|title=Water and the Land|year=1993|publisher=Adams Publishing Corp.|location=Cathedral City, CA|isbn=0935030026|pages=35–36}}</ref> by the farmer Frank Zybach,<ref name="WiredMagazine">{{cite magazine | url=https://www.wired.com/science/discoveries/news/2008/07/dayintch_0722 | title=July 22, 1952: Genuine Crop-Circle Maker Patented | magazine=Wired Magazine | date=July 22, 2008 | access-date=June 6, 2012 | author=Alfred, Randy}}</ref> who lived in [[Strasburg, Colorado]].<ref name="Morgan 1993 35–36"/> It is recognized as an effective method to improve water distribution to fields.<ref name="NASA1"/>

In 1952, Zybach went into business with A. E. Trowbridge, a friend, Ethan James Olson, from Columbus, Nebraska. Trowbridge put up $25,000 ({{Inflation|US|25000|1952|r=-3|fmt=eq}}) and got 49% of the patent rights. Zybach moved back from Colorado to Columbus, opened a shop, hired a few men, moved the height of the pipe up to {{convert|6|ft|m|1|order=flip|abbr=on}}, and went into business. In the first two years of operation, they sold only 19 systems. The early designs were finicky and few farmers understood the systems. Zybach kept improving his designs and focused on making his machines better, rather than attempting to sell systems with problems.<ref>{{Cite web|url=https://livinghistoryfarm.org/farminginthe50s/water_03.html|title=Center Pivot Irrigation Systems Take over During the 1950s|access-date=December 12, 2018|archive-date=January 21, 2022|archive-url=https://web.archive.org/web/20220121142028/https://livinghistoryfarm.org/farminginthe50s/water_03.html|url-status=dead}}</ref>

Zybach saw success with modified designs, which improved the systems operational efficiency. In 1954, he licensed his patent to Robert Daugherty and his company, Valley Manufacturing. Daugherty's engineers spent the next decade refining Zybach's innovation, making it sturdier, taller, and more reliable, and converting it from a hydraulic power system to electric drive. Daugherty's company went on to grow into [[Valmont Industries]], with Valley Irrigation being its subsidiary.<ref>{{Cite web|url=http://www.valleyirrigation.com/about-us/history|title=Valley Irrigation's History}}</ref>