The state Legislature and Gov. Terry Branstad have stepped up to support the implementation of the Iowa Nutrient Reduction strategy, state agriculture officials said. Now it’s time for Iowa farmers to voluntarily implement additional incremental changes to reduce losses of nitrogen and phosphorus from their fields, they said.

"We need to make this happen," Iowa Agriculture Secretary Bill Northey said recently during a presentation to the 2013 Iowa Farm Bureau Federation Economic Summit in Ames. "If we do this the right way, we are going to get the dual impact of improved water quality off the farm and better performance on our farms."

Calls for mandatory...