Nathan Bomey

USA TODAY

The Obama administration on Wednesday filed an antitrust lawsuit seeking to block a low-profile deal between two high-profile agricultural industry suppliers, Deere (DE) and Monsanto (MON), describing the decision as necessary to protect farmers.

The Justice Department sought to block Deere's acquisition of Monsanto's Precision Planting, which was initially revealed in November.

The deal threatened to give Deere a stranglehold on the market for high-speed precision-planting devices, the government charged. Together, Deere and Monsanto sell 86% of all equipment in the precision-planting sector, according to the government.

The Justice Department's action comes amid a flurry of mergers and acquisitions in the agricultural industry, potentially signaling greater antitrust scrutiny to come, even as the sector sags amid declining crop prices.

"If this deal were allowed to proceed, Deere would dominate the market for high-speed precision-planting systems and be able to raise prices and slow innovation at the expense of American farmers who rely on these systems," said Renata Hesse, acting assistant attorney general of Justice's antitrust division, in a statement.

Though Precision Planting's 2015 sales were only about $100 million — a relatively insignificant amount for giant firms like Monsanto and Deere — antitrust officials said the technology will "become the industry standard in the coming years," replacing conventional planters.

Deere and Monsanto pledged to fight the lawsuit, saying that the deal will increase the availability of the technology and that competition is "strong and growing."

"DOJ’s allegations about the competitive impacts of the transaction are misguided and the companies intend to defend the transaction vigorously against those allegations," the companies said in a statement. "The proposed acquisition benefits farmers by accelerating the development and delivery of new precision equipment solutions that help farmers increase yield and productivity."

Stocks of Deere and Monsanto were already down for the day when Justice officials revealed their action at noon and moved little afterward. Deere was down 1.3% to $84.67 at 3:43 p.m., and Monsanto was down 0.9% to $106.50.

Bayer could face rival for $62B Monsanto takeover

The deal was part of a bevy of tie-ups and acquisition talks reshaping the world of agricultural equipment, seed, fertilizer and pesticides:

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.