Seed-corn giant Monsanto will embark on a $100 million-plus expansion at its processing plant near Waco and at three sister plants in Iowa and Indiana, its top commercial corn manufacturing official announced Wednesday.

The expansion along U.S. 34 between Utica and Waco comes just a year after the St. Louis-based company celebrated the opening of a $135 million corn and soybean seed plant at the same location just west of the Seward-York County border.

“We needed to add capacity. It’s a great opportunity to bring additional capacity on line,” Shawn Schrader said in a telephone interview.

Although the investment will be divided up among four projects, most of the money will be spent in Nebraska and Indiana because those are most closely linked to plans to ramp up production.

Dirt work will start at the Waco site in December. Schrader said there’s space available for more dryers and receiving, sorting and husking chores on the 160 acres the company already owns there.

“We hope to be operational by August 2013,” he said.

Monsanto, once a major producer of plastics and chemicals, now concentrates on biotechnology. Its Roundup-ready soybeans, genetically modified to be herbicide-tolerant, have been a huge success.

It has more than 21,000 employees worldwide and had $11.8 billion in revenue in 2011.

Along with Pioneer, Syngenta and Mycogen, each of which has a major presence in Nebraska, Monsanto is dominant in the seed-corn business.

“The big dog right now is Monsanto,” said Dale Flowerday, a Lincoln crop consultant and former Pioneer employee.

Schrader referred to competition with Pioneer as “probably neck and neck.”

Outside observer Flowerday said Wednesday’s news is the most recent example of major seed-industry players moving production under irrigation to guard against drought conditions such as those experienced in Nebraska and surrounding states this year.

Schrader acknowledged that point.

“The Waco facility today is 100 percent irrigated,” he said. “That’s our objective: to gain all those acres under irrigation.”

Drought tolerance is an area of emphasis right now in developing new seed-corn varieties.

Farmers contract with companies to raise seed corn in their fields.

Thousands of teenagers step forward every summer to pull pollen-producing tassels off corn stalks and help assure the cross-pollination that leads to hybrid vigor.

Flowerday said companies want locations that are close to both irrigation and the potential seasonal labor pools in Lincoln and other trade centers. That helps make the Seward-Utica area “kind of a hotbed of seed-corn production.”

Monsanto employs about 70 people full time at Waco. Schrader wasn’t ready to say how many more full-time and seasonal workers might be added after the expansion or how much will be spent on construction there.

He did say Monsanto representatives will reach out to both existing and new growers in a 40- to 50-mile radius to boost acres. That area adjoins the production circle that serves a similar plant at Kearney.

Although irrigation is seen as an attraction in Nebraska, Flowerday said the demands for irrigation water in drought years lower the water table and can threaten water supplies for both agriculture and human use.

Because of the big investment, those involved in seed-corn production are especially careful about applying enough water in irrigated settings to prevent crop stress and yield reduction.

Depending on how long this drought lasts, allocation of water could happen in one or more of the state’s 23 natural resources districts, Flowerday said.

“That’s a very, very reasonable concern,” he said, “and a reasonable concern for Nebraska.”

Schrader said sustainability is a Monsanto priority.

“And obviously water usage and water usage to produce crops is an issue to focus on.”

The company has a Water Utilization Learning Center and a 324-acre research farm at Gothenburg meant to delve into such questions as managing drought and water efficiency.

Reach Art Hovey at 402-473-7223 or at ahovey@journalstar.com