Soil Sample Preparation (IMAGE) American Society of Agronomy Caption Preparation of soil sample for visible near-infrared spectroscopy measurement. An air-dried and 2-mm sieved soil sample is poured into a rotating sample cup with transparent quartz window. Credit Maria Knadel 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.