The Cornell University researchers said knowing the structure and detailed composition of soil carbon might help scientists understand what happens when materials in the soil become wet, warm or cool and how soils sequester carbon, which has implications for climate change.

"There is this incredible nanoscale heterogeneity of organic matter in terms of soil," said Associate Professor Johannes Lehmann, lead author of the study. "None of these compounds that you can see on a nanoscale level looks anything close to the sum of the entire organic matter."

The soil measurements were made at the National Synchrotron Light Source at Brookhaven National Laboratory using an X-ray spectromicroscopy method developed by physicists at the State University of New York-Stony Brook

The research was funded by the National Science Foundation and is detailed in the journal Nature Geoscience.