But National Farmers Union President Roger Johnson pointed out that “with the downturn of the agricultural economy, the entire agriculture sector is engaged in rapid consolidation” — a trend he described as troubling.

If all three pending deals close, three companies would account for nearly 80 percent of U.S. corn seed sales and nearly 70 percent of the global pesticide market, he said, resulting in “fewer choices for farmers, higher prices and less innovation,” he said.

“Any arguments that integration is an efficiency should be viewed with skepticism,” added Diana Moss, president of the American Antitrust Institute.

Judiciary Chairman Chuck Grassley, R-Iowa, pointed out that the acquisitions come after corn prices fell from $7 a bushel in 2012 to under $3, and that overall farm income this year is expected to be well below record highs of recent years.

He said that “there is a lot of interest in how these transactions will recalibrate the seed and chemical world, and whether they’ll pass regulatory muster.”

“I am afraid this consolidation wave may have become a tsunami,” he said.