Fred Pearce takes a visit to a Kenyan valley where environmental theory has been turned on its head
Jane Ngei, a 30-year-old Kenyan mother and farmer, built her own dam with an ox-plough, spade and wheelbarrow. It’s not a big dam; less than 15m across. “It collects the water running down the road after it rains,” she explains. It irrigates her half-dozen hectares of maize, vegetables and fruit trees, and keeps her small herd of cattle and goats watered.
Hardly the kind of dam to turn back the tide of history, you might think. Yet, scientists from all over the world keep dropping in to discover if Ngei has found the secret of how to halt the advance of the world’s deserts and save Africa from an ecological Armageddon.
According to conventional environmental wisdom, Ngei’s farm and hundreds of others throughout the drought-prone hills of Machakos district, east of Nairobi, should not be here. This landscape should long since have turned to dust and blown away.
Sixty years ago, British colonial soil inspector Colin Mather condemned these hills as “an appalling example” of environmental degradation in which “the inhabitants are rapidly drifting to a state of hopeless and miserable poverty and their land to a parched desert of rocks, stones and sand”. Much the same was said in the 1950s and again in the 1970s.
And through that period, with Kenya recording the fastest population growth rate in the world, the population of Machakos district rose a staggering fivefold. A recipe for disaster, surely? And yet, these hills have failed to turn to desert.
Today, they are greener and more heavily planted with trees, more productive and less eroded, than ever.
What went right? Some say that rising population was the best thing that happened. It forced the farmers to change from cattle herding to settled farming. And it gave them the labour to work the land properly.
Ngei is one of hundreds of farmers in these hills, the heartland of the Akamba people, who have dug dams, planted trees and constructed terraces up the steep hillsides to trap rainfall and prevent soil washing away.
It sounds simple. Yet this environmental transformation has become known as the “Machakos miracle”. And by refusing to bow to the apparently inevitable, the Akamba farmers have offered a challenge to the doomsayers of desertification.
It is a challenge in particular to the scientists at the United Nations Environment Programme, whose world headquarters are an hour’s drive from Machakos in the Nairobi suburb of Gigiri.
For two decades, that agency has warned of rampant worldwide desertification. It has mapped the arid east of Kenya, including much of Machakos district, as a prime target for advancing deserts.
Have its scientists come to find out why, on their very doorstep, those predictions are being confounded? If so, there is no record of it.
If they had come, they would have met Akamba farmers who saw terraces for the first time while serving in India during World War II, and decided to try them out back home. And dam-building farmers like Ngei. And crop innovators like Joseph Kisalu in Ukalani, who deliberately cross-pollinates Katumani maize from the research station with older local varieties, as well as inter-cropping cowpeas and sunflowers with his maize to improve soil fertility.
What was once a subsistence economy, geared to nothing more than survival on crumbling soils, has turned into something much more productive and environmentally sustainable.
“Farmers here grow maize to eat, but everything else for cash,” says Benjamin Ikombo, a soil and water expert at the nearby National Drylands Research Station, who in his spare time tends 5ha of hillside.
Boxes of his mangoes, oranges and paw-paws are regularly exported from Nairobi International airport to Europe and the Middle East.
Others sell coffee, French beans and tomatoes. No less valuably, Ngei’s six head of cattle contribute milk for an expanding dairy in nearby Masii town, which sells its products as far away as Nairobi. Desertification this isn’t.
Some outside researchers have come to see. Michael Mortimore and Mary Tiffen, from Britain’s Overseas Development Institute, investigated the Machakos miracle in their book More People, Less Erosion (John Wiley, 1994).
It is genuine, they say. A vicious circle of environmental decline, fuelled by population growth, has been turned into a circle of virtue. Yes, says Mortimore, “there are more mouths to feed; but there are also more brains to think and hands to work”. And in Machakos at least, the brains and hands have won.
That book has become a standard text for both environmental optimists and free- market economists, who see in it the triumph of private farming enterprise over state planning. (A bit simplistic that last claim. Exports need good roads and most of the Machakos terraces have been dug by communal effort, often organised by women’s groups.)
Some insist Machakos is a one-off. Its proximity to Nairobi provides an easy market for produce and financial capital for investment in farming that other communities across the arid lands of Africa could not match.
There is no doubting the importance of Nairobi, says Mortimore. He has, for 20 years, charted a similar virtuous circle in the arid farming zone around the city of Kano in northern Nigeria.
“Maybe we need more Nairobis and Kanos as well as more Machakoses,” he says. That proposition, too, cuts across the grain of green theory, which holds that Third World cities are leeches on the farmland around them. Not here.
But Ikombo warns against too much optimism. “Mortimore and Tiffen are right about declining soil erosion here,” he says. “But the big problem in Machakos today is declining soil fertility.”
The new intensive farming means soils no longer lie fallow. They need more nitrogen in particular, either from manure (in short supply as farmers give up cattle for crops) or from artificial fertiliser (which poorer farmers cannot afford). And drought could still bring malnutrition to some people here, especially in the driest areas.
But whatever the problems, the big story from Machakos is that the region has bucked the conventional wisdom and offered a lifeline to a country, indeed to a continent, whose population is expected to triple within the lifetime of today’s children. For now at least, Ngei’s children look remarkably well fed on fields that really just shouldn’t be here any more.