Soil microbes can be used to trace dust to its source. Soil microbiologist Ann Kennedy checks a computer map that shows the location of various biological groupings across the Columbia Plateau in Washington State.

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from the USDA’s rich science and research profile.

Even back in the days of Mark Twain’s riveting tales of steamboat pilots and derring-do on the Mississippi River, it was known that you could catch a crook by means of almost invisible clues left at the scene of the crime:  the unique patterns of his fingertips.  How do we know this? In Twain’s “Life on the Mississippi,” published in 1883, a murderer was identified by his fingerprints.

So in these days of high-tech crime shows where the tiniest shred of earthly remains can do practically everything but provide the victim’s home address, fingerprints might seem a bit passé—more Barney Fife than “NCIS.” But in fact, USDA scientists are using a form of fingerprints in an innovative way that ultimately could help keep us all healthy—and well-fed.

Soil erosion from wind, water and other forces has plagued American agriculture for centuries. That’s why scientists from USDA’s Agricultural Research Service are identifying practices that will keep this valuable soil out of the air and on the field where it’s needed.

In their studies, the scientists have discovered that soils can be “fingerprinted” on the basis of the fat content of microbes living in the soil.  Each microbe community has a unique fingerprint that can be used to identify the soil.  Sediment deposited far downwind from a field can potentially be traced back to its origin.

Knowing the soil’s source can provide clues regarding which farm management practices are more (or less) likely to hold soil in its rightful place.  Ultimately, the scientists want to pinpoint the practices that reduce soil’s vulnerability to wind erosion and keep rich topsoil where it belongs—on the fields, producing crops to feed our nation and the world.