Kura clover (IMAGE) Purdue University Caption Kura clover, which adds nitrogen to the soil, grows at Purdue University’s Water Quality Field Station. Credit Purdue Agricultural Communications / Joshua Clark Usage Restrictions News organizations may use this image in reports about the work of Purdue University's Yichao Rui and his collaborators. License Original content 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.