Land mines are not only explosive but also poisonous, leaking toxins into the soil that make plants sick. That's unfortunate for the plants but fortunate for us—if we can figure out how to look for sick plants as harbingers of land mines. Aeroplanes equipped with a low-cost sensor that captures non-visible light might be the answer.
LiveScience's Becky Oskin reports from the annual meeting of Ecological Society of America, where a group of researchers from Virginia Commonwealth University are presenting just this idea. That a bunch of ecologists would be interested in land mines actually makes a lot of sense; land mines lurking underground can subtly shape the ecology of an area.
The VCU researchers did their field research at an unusual place though, a "privately owned experimental minefield in South Carolina, where [DARPA] once buried fake land mines for a research project," writes Oskin. The National Explosives Waste Technology and Evaluation Center is where researchers can (safely) experiment on new ways to detect land mines.
At the experimental mine field, VCU researchers found that not all plants reacted to explosives like TNT and RDX the same. Woody plants were less affected than herbaceous ones with soft stems. On the other hand, common weeds like the nutsedge seemed completely unaffected. The makeup and health of an area with dense vegetation—where traditional mine detection methods might be difficult—could be a clue to land mines underneath. To that end, the researchers envision an entire "Explosive Specific Index" cataloguing how buried explosives affect different plants.
The key, though, is a fast and cheap way to scan across large swathes of vegetation. That could mean hyperspectral imaging from aeroplanes or from the ground. Hyperspectral imaging can also light outside of the visible spectrum, which is helpful because infrared, for example, can reveal damage that doesn't show up in visible light. Plants could one day reveal secrets long buried underground, if we just know what to look for. [LiveScience]
Top image: Land mine being defused in Cambodia. AP Photo/Heng Sinith