The Department of Defense is looking at ways to clean up the hundreds of thousands of training rounds used by the U.S. army. It is putting out the call for the development of biodegradable ammunition loaded with seeds that sprout plans after being discharged. New Atlas reports: At military facilities across the U.S. and indeed around the world, a huge number of rounds are fired for training purposes, ranging from low-velocity 40 mm grenades, to mortars, to 155 mm artillery rounds. All of these feature components that can take hundreds of years to biodegrade, and falling onto the ground in such great numbers means that finding and cleaning them up is no small task. But left behind, they can corrode and pollute the soil and water supplies. So the Department of Defense has put out a call for proposals through the Small Business Innovation Research agency that solve the problem. The DoD describes the solution as a naturally occurring biodegradable material that can replace those used in current training rounds. It imagines that the biodegradable composites will be capable of holding bioengineered seeds inside (a technology it says has been demonstrated previously), that won't germinate until they have been in the ground for several months. Then plants will sprout from the discharged ammunition that actively remove soil contaminants and consume the other biodegradable components. Also imperative is that animals are able to safely consume the plants.