When they were forming Micron Technology Inc. in the late 1970s, the founders of the Boise, Idaho, maker of semiconductors didn’t seek their initial funding from venture capitalists in Silicon Valley. Instead, they sat down with a potato farmer, a rancher and a building contractor in Idaho.

The three men kicked in $300,000 of seed money for what is today a global producer of memory chips with a stock-market value of about $85 billion.

One of those three early investors was Allen T. Noble, who died July 18 at his home in Boise. He was 92.

Mr. Noble grew potatoes and other crops and owned farm-equipment dealerships. Though he never went to college, he invented self-propelled irrigation machinery that could shuttle across fields. His interest in technology put him in contact with two of the founders of Micron— Joseph L. Parkinson, a lawyer, and Mr. Parkinson’s twin brother, Ward, a semiconductor-design engineer who had worked for Mostek Corp.

Allen Noble owned farm-equipment dealerships and invented irrigation machinery.

Photo: Noble Family

At the time, Micron’s founders were working in the basement of a dentist’s office in Boise. The three initial funders saw the potential and then helped reel in another early financial backer, J.R. Simplot, the billionaire potato farmer who supplied McDonald’s Corp. with frozen french fries.

Mr. Noble served as a director of Micron until 1996, when he resigned amid tension between the board and the chief executive at that time, Steve Appleton.

Micron survived fierce price competition from Japanese rivals in the 1980s and today is one of the world’s three major makers of DRAM memory chips, along with Samsung Electronics Co. and SK Hynix Inc. of South Korea, said Dan Hutcheson, CEO of market research firm VLSIresearch. Micron “proved America could compete in semiconductor manufacturing on cost,” said Mr. Hutcheson, who added that Mr. Noble understood the need to squeeze costs in a commodity market. After all, he was a potato farmer.

Allen Thomas Noble was born Dec. 20, 1928, in Idaho Falls, Idaho. He grew up on a family farm in Kuna, Idaho, graduated from high school in 1946 and married Vera May Shulz. They initially farmed and milked cows for neighbors and eventually bought their own dairy and farm machinery. Mr. Noble also bought a stake in an International Harvester dealership in Nampa, Idaho.

In the early 1960s, he spotted a patch of arid land near Nampa and invested in equipment to pump water up steeply from the Snake River to provide irrigation. “It’s the richest land I ever saw,” he told the Idaho Statesman in 1962. Before planting potatoes, he had to arrange for uprooting of sagebrush and clearing bombs left in the ground at what was a World War II bombing range. “They found quite a few,” he said.

Later, as he refined his automated irrigation system, Mr. Noble sought help on the electronics from Ward Parkinson. That created a friendship that proved critical for Micron.

Seeking local backers for the company, Joseph Parkinson invited Mr. Noble, Thomas T. Nicholson and Ronald C. Yanke to lunch at a Boise restaurant. The three men showed “enormous courage” and “put everything they had at risk,” Mr. Parkinson said. As of mid-1984, their shareholdings in the company totaled 26%.

Mr. Noble donated some of his wealth to Boise State University, where he was the lead donor for an expansion of a football stadium.

Mr. Noble’s first marriage ended in divorce. In 1965, he married Billie Dee Jolley Johnson, who had worked as a florist. She died in 2017. His survivors include a brother, a sister, seven children, 22 grandchildren and 54 great grandchildren.

Write to James R. Hagerty at bob.hagerty@wsj.com