Agronomy Farm (image) Iowa State University Caption The research plot on the Iowa State University Agronomy Farm shows how different combinations of cover crop and corn net different results. Early research has shown that with some combinations, almost all crop stover can be removed for biofuels while yields remain high and soil improves. Credit ISU photo by Dan Kuester Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.