Tony Vyn, Purdue University (IMAGE) Purdue University Caption Purdue agronomist Tony Vyn found that high yields were linked to corn's absorption of nutrients at specific ratios -- 5-to-1 for nitrogen to phosphorus and 1-to-1 for nitrogen to potassium. Credit Purdue University / Tom Campbell Usage Restrictions Please credit Purdue University / Tom Campbell. License Licensed 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.