Iowa farmers have pulled nearly 750,000 idled acres back into production in a seven-year span, undermining conservation efforts that are crucial to improving the state’s poor water quality, a new report says.

Roller-coaster corn and soybean prices have spurred farmers in Iowa and across the nation to remove nearly 16 million acres from the federal Conservation Reserve Program, commonly referred to as CRP, between fiscal years 2007 and 2014, the Environmental Working Group said in a study released Wednesday.

As a result, Iowa taxpayers lost nearly $760 million in environmental benefits from farm conservation program as protective ground cover was plowed under to grow more crops, a new report says.

“We need these critical…