It is possible to make Africa's degraded drylands productive again, said researchers at a symposium held in Niamey, Niger last week (23-25 September).
They showed that dryland degradation can be reversed if farmers, researchers and governments invest in planting trees, farming more sustainably and replenishing groundwater.
Increased human and livestock populations in drylands over the last century have led to severe land degradation, particularly in sub-Saharan Africa. The Millennium Ecosystem Assessment estimated that 10-20 per cent of the world's drylands — an area more than twice that of India — are significantly degraded.
But rehabilitation efforts have picked up in the past 30 years and farmer-led initiatives are producing results.
Researchers in Niger have found that farmers have rehabilitated three million hectares of severely degraded land by their own initiative.
"The scale and speed of this phenomenon is surprising," says Chris Reij, of Vrije University in the Netherlands. "Where few trees could be found in the mid-1980s, one now finds 20 to 150 trees per hectare."
The farmers have been protecting the re-growth of natural vegetation, which has improved soil fertility and broken down the hard crust that forms over soils. They have also been integrating agriculture, livestock and forestry, resulting in a substantial increase in farm productivity.
"This really represents a reversal of the spiral of degradation which characterised the 1970s and 1980s," says Reij.
Reij points out that this been farmer-led, but that formal research is set to play a bigger role in the future, for instance by offering more technical solutions that farmers can apply to local conditions.
Farmers have also improved the productivity of 200,000 hectares in Burkina Faso.
The symposium heard how in northern Ethiopia, ten years of tree planting and soil conservation measures have stimulated the re-growth of vegetation. Selling wood also provides extra security for farmers.
Mark Winslow, a scientist at the International Crops Research Institute for the Semi-Arid Tropics, which helped to organise the meeting, points out that land rehabilitation does not generally lead to its full recovery.
Typically the land can be restored to 50-75 per cent of its former productivity, "though this depends on the particular soil and economic conditions", he told SciDev.Net.
Participants at the meeting adopted a declaration urging scientists to address the needs of the poor.
Their recommendations included that research be focused on dryland policy options, farmer decision-making and incentives, and on interactions between agricultural and natural ecosystems.