Africa faces a crisis of soil organic material that will cause an unprecedented famine in five to ten years, said experts at ICRAF last week.
"Soil fertility is getting worse," said Wilson Songa, the Agriculture ministry PS, who opened the Beating Famine conference at the World Agroforestry Centre last week.
"Fallowing used to take care of soil fertility," said renowned agro-ecologist Roland Bunch. "It contributed between 80 to 90 per cent of all organic material in soil." But today 80 per cent of African farmers have less than two hectares and cannot rest their land. Fallows of less than four to five years do not restore fertility.
Besides the end of fallowing, three other factors are collapsing harvests: global warming, soaring fertiliser prices, and a drop in the supply of manure as livestock numbers fall. Over 150 million people in drought-prone areas will suffer. "Drought ends when it rains," said Bunch. "But soil fertility problems only end when farmers change their practices."
The conference called for the integration of trees in farming to regenerate the land and beat famine. Mahamane Larwanou of the African Forestry Forum said, "trees are so important for a good harvest. They are granaries."
He described a new approach called farmer-managed natural regeneration (FMNR). Pioneered in Niger, FMNR has re-greened five million hectares, an area the size of Costa Rica.
By allowing stumps to regrow and pruning the regrowth, farmers gained 200 million new trees. This compares to 60 million trees planted in Niger over the last 20 years of which less than 20 per cent survived.
The conventional wisdom is that trees compete with crops, said Larwanou. But land under FMNR produces an extra 500,000 tonnes of cereals a year, enough for 2.5 million extra people. Cattle and goat numbers have also risen as grassland regrew. Trees fix nitrogen, increase humidity, and provide fodder.
Tony Rinaudo of World Vision, the missionary who stumbled upon the method in the 1980s, said, "in Africa there is an underground forest waiting to be released. 50 per cent of the biomass is under the ground. We need to allow it to come back."