Land O’Lakes Inc. and United Suppliers Inc. are merging their crops inputs units, forming a business ­division with more than $7 billion in annual sales.

Under the agreement announced by the companies, United Suppliers’ crop protection and seed business, which had $2.6 billion in 2014 sales, will join with WinField LLC, Land O’Lakes’ crop inputs and seed business with $4.9 billion in sales last year.

The companies said the merger will provide expanded product offerings, enhanced precision agriculture ­services and improved product insights and consulting.

“This move comes at a time when scale is increasingly important in addressing changing industry dynamics,” said Chris Policinski, president and CEO of Arden Hills-based Land O’Lakes. Those changes include rapid consolidation, fast-paced technological innovation, and the need for more service ­offerings for customers.

The merger builds on recent successes of the two companies and aims to create a “single, strong, relevant and competitive entity,” the release said.

It would be a two-stage process, with the companies first combining their seed and crop protection businesses, which includes herbicides, pesticides and fungicides, and later adding the crop nutrient business.

Members of Land O’Lakes and owners of United Suppliers will need to approve details of the merger, and votes are scheduled in August. The closing is expected in October.

Land O’Lakes is one of the nation’s largest cooperatives, with annual sales of more than $15 billion last year, known for dairy and other consumer foods and a broad supplier of farmer production services.

United Suppliers is a customer-owned wholesale supplier of crop protection products, seeds and crop nutrients. With headquarters in Ames and Eldora, Iowa, it includes 600 agricultural dealers in nearly 2,800 retail locations in the U.S. and Canada.