An ancient soil-enrichment strategy practiced by West African farmers could boost agricultural yields across the continent and help farmers mitigate the negative effects of global warming.

For at least 700 years, villagers in West Africa have replenished nutrient-poor rain forest soils with charcoal and kitchen waste, transforming the lifeless dirt into rich, fertile compost.

A team of researchers from Europe, the United States and West Africa tested soil from dozens of sites in Ghana and Liberia and found 200 to 300 percent more organic carbon than unenriched soil. The scientists detailed their findings in the journal Frontiers in Ecology and the Environment.

Researchers say the fortified soils, which they've dubbed "African Dark Earths," can better sustain intensive farming than other less fertile soils in Africa.

"Mimicking this ancient method has the potential to transform the lives of thousands of people living in some of the most poverty and hunger stricken regions in Africa," lead researcher James Fairhead, from the University of Sussex, said in a news release. "More work needs to be done but this simple, effective farming practice could be an answer to major global challenges such as developing 'climate smart' agricultural systems which can feed growing populations and adapt to climate change."

Similarly rich soils, enhanced by ancient Amazonian farmers, have been found in South America, but their enrichment techniques aren't yet known.

"What is most surprising is that in both Africa and in Amazonia, these two isolated indigenous communities living far apart in distance and time were able to achieve something that the modern-day agricultural management practices could not achieve until now," said lead study author Dawit Solomon, from Cornell University.

"The discovery of this indigenous climate smart soil-management practice is extremely timely," Solomon added. "This valuable strategy to improve soil fertility while also contributing to climate change mitigation and adaptation in Africa could become an important component of the global climate smart agricultural management strategy to achieve food security."