University of Wisconsin researchers investigated yield differences between organic and conventional cash grain and forage crops in the Upper Midwest.

The scientists based their study on results from the Wisconsin Integrated Cropping Systems Trials, conducted 1990-to-2002 at Arlington, Wis., and from 1990-to-1997 at Elkhorn, Wis.

The trials compared six cropping systems -- three cash grain and three forage based crops -- ranging from diverse organic systems to less diverse conventional systems.

The scientists found organic forage crops yielded as much or more dry matter as their conventional counterparts with quality sufficient to produce as much milk as the conventional systems. Organic grain crops produced 90 percent as well.

"There continues to be improvements in weed control for organic systems that may close the gap in productivity of corn and soybeans in wet seasons," said Professor Joshua Posner, the study's author. "On the other hand, technological advances may accelerate productivity gains in conventional systems that would outstrip the gains in organic systems even in favorable years."

The research is reported in the April issue of the Agronomy Journal.