Iowa News Service
Des Moines, Iowa — September 13, 2011
Iowa farmers have long used a two-crop rotation to keep the yields up in their fields, but new research at Iowa State University (ISU) indicates they could increase their yields even more by using a third crop in the rotation cycle.
ISU agronomist Matt Liebman says an example is the boost soybeans get from using three crops instead of two. "We've seen a gain from 42 bushels an acre in the two-year rotation up to 54 and 55 bushels an acre in the three-year and the four-year rotations."
Liebman says rotation can reduce the impact of "soybean sudden death syndrome (SDS)" and increase weed seed predators. "And we get outstanding weed control; that's important now, because we are starting to see resistance to glyphosate."
He says the three-year plan is a corn-soybean-oat and red clover rotation. Essentially, he says, it allows a farmer to "grow his own nitrogen" and reduce having to purchase inputs, which leads to higher profits.