Calcium Carbonate (IMAGE) American Society of Agronomy Caption Extensive calcium carbonate accumulation engulfs this soil layer, making it difficult for plant roots to break through. Credit David C. Weindorf. 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.