Geotimes Videocast Thursday, June 5, 2008
Black gold agriculture
Charcoal is making a comeback — but not where you might think. Instead of putting charcoal into the grill, some scientists are advocating putting it into the ground.
They say the strategy, dubbed "black gold agriculture," can boost soil fertility by attracting microbes, trapping moisture and helping the soil hold nutrients.
The idea that charcoal, also known as biochar, can improve soil is not new. People in the Amazon were adding charcoal to the soil hundreds of years ago. Today, the black earth they created — called terra preta in Portuguese — is still so fertile that local residents sell it as compost.
But there's another benefit that's grabbing scientists' attention: charcoal can sequester carbon. Organic wastes such as corn stalks and peanut shells are often burned or left to decompose. Both activities release carbon dioxide. But when such wastes are charred, much of the carbon gets trapped.
When charcoal is added to soil, it can hold onto its carbon for hundreds or even thousands of years.
For more on this topic, see the July issue of Geotimes.