Test Tubes (IMAGE) American Society of Agronomy Caption Soil protein is measured in the lab using a color-reading process called colorimetric analysis. Credit Steve W. Culman 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.