Center Pivots Take Over

pivot irrigation systemsIn June 1976, Scientific American magazine called center pivot irrigation systems “perhaps the most significant mechanical innovation in agriculture since the replacement of draft animals by the tractor.” The author, William E. Splinter, was a professor of agricultural engineering at the University of Nebraska-Lincoln, so he could be accused of some bias. But he was also probably not far off the mark.

Just 25 years after Frank Zybach invented the first center pivot system, there were almost 10,000 center pivot systems in operation in Nebraska alone. U.S astronauts could clearly pick out the Northeast Nebraska region from 270 miles in space by the patterns of lush, green crop circles produced by center pivots.

But in the 1950s and 60s, center pivot irrigation was a promising concept with a lot of technical hurdles to overcome. Frank Zybach’s first experimental system – built in 1947-8 – had two sections of pipe suspended by cables from two towers and ran on skids. By 1949, he had built a five-tower system on wheels that ran two to three feet off the ground and could irrigate 40 acres. Zybach built his own water valves to both push the wheels and to keep the various towers in line. That was enough to file for a patent on the technology, and he won patent protection for his invention in 1952.

But there were problems. A two to three foot clearance would work fine on low crops like sugar beets or alfalfa. But most of the Midwest was planted in seven-foot tall corn. Also, he couldn’t keep building systems in his backyard blacksmith shop and expect to make any money on his patented technology.

So, in 1952, Zybach went into business with A. E. Trowbridge, a friend and car dealer from Columbus, Nebraska. Troybridge put up $25,000 and got 49 per cent 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 six feet and went into business.

film_obermier_RIn the first two years of operation, they sold only 19 systems. The early systems were finicky and very few farmers could see how this ungainly looking system could work.

York Nebraska farmer Virgil Obermier (left) remembers what he thought the first time he saw a center pivot system. “I said, ‘Can’t work.’ [He laughs.] You know, to have it fastened in the center and walk in a circle and then the sprinklers put a little water in the center and a lot out in the end? [It can’t work.]”

Zybach was more of an inventor than a salesman. So, in the face of doubts from potential customers, he kept tinkering and made the machines better rather than pushing farmers to buy systems with problems. Trowbridge, the businessman, saw that if they couldn’t sell enough machines before a new “product line” was introduced, they couldn’t make money.

So, as early as 1954, they started talks with Robert Daugherty, the young owner of a small farm equipment manufacturing company, Valley Manufacturing. It would be Daugherty who took Zybach’s invention and built it into “the most significant mechanical innovation in agriculture since the replacement of draft animals by the tractor.”
The modern center pivot irrigation system has come a long way. It’s now a computer controlled system with high-tech engineering solutions to the problems of supporting the weight of the water, distibuting it evenly across huge, undulating fields and even swinging out another arm to get water to the corners of square fields.
You can see how this technology comes together in this video segment about the installation of a pivot system

Written by Bill Ganzel, the Ganzel Group. First published in 2006. A partial bibliography of sources is here.

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