The technique known as "African dark earths" transforms nutrient-poor rainforest soil into fertile farmland

By Kieran Guilbert

DAKAR, June 21 (Thomson Reuters Foundation) - A farming technique practised for centuries in West Africa, which transforms nutrient-poor rainforest soil into fertile farmland, could combat climate change and revolutionise farming across the continent, researchers said on Tuesday.

Adding kitchen waste and charcoal to tropical soil can turn it into fertile, black soil which traps carbon and reduces emissions of greenhouse gases into the atmosphere, according to a study carried out by the University of Sussex in England.

The soils produced by the 700-year-old practice, known as "African dark earths", contain up to 300 percent more organic carbon than other soils, and are capable of supporting far more intensive farming, said the anthropologist behind the study.

"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," said James Fairhead, Professor of Anthropology at the University of Sussex.

The research was carried out by anthropologists and soil scientists who lived with communities in Liberia and Ghana while analysing almost 200 sites across the countries, the study said.

A previous top-down approach from the scientific community and lack of engagement with African farmers may explain why such a simple method had not been studied until now, Fairhead said.

"Relations of power in West Africa had been hiding the skills and wisdom of local farmers," he told the Thomson Reuters Foundation.

"Scientists need to pay more attention and respect to existing practices, especially if these practices can boost food production and sequester carbon."

Similar soils created by pre-Columbian era inhabitants of Brazil's Amazon forest have recently been discovered, said Dawit Solomon, author of the study published last week in the journal Frontiers in Ecology and Environment.

"What is most surprising is that ... 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," he said.

An estimated 180 million people in sub-Saharan Africa are affected by soil degradation, which costs them $68 billion a year, according to a 2014 report by Agriculture for Impact.

Climate change, desertification, the depletion of mineral nutrients, improper use of fertilizer and a lack of infrastructure are compounding the problem, the report found.

(Reporting By Kieran Guilbert, Editing by Emma Batha. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit news.trust.org)

Our Standards: The Thomson Reuters Trust Principles.