Two Years Later (IMAGE) American Society of Agronomy Caption Water control box at a saturated buffer two years after installation. All of the nitrate removal 'work' is done underground by the soil and soil microbes. Credit Dan Jaynes Usage Restrictions Please use with story only. 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.