Desert harvest

IT MUST be true. We’ve been told it so many times. The over-farmed and overgrazed soils of Africa, especially on the fringes of the Sahara, are losing their fertility and eroding away. As the population grows, poor farmers are mining the last goodness from their soils. Their animals graze the grasslands away to nothing and the desert sands move in. Environmentalists say it; development economists say it; politicians say it; soil scientists say it.

“An area the size of Somalia has become desert over the past 50 years. The same fate now threatens more than one-third of the African continent,” says the UN Food and Agriculture Organization, adding that “the main cause is mismanagement of the land.” Its sister body the UN Environment Programme claims that 900 million Africans face starvation as their soils crumble away. UNEP masterminded a UN Desertification Convention in 1996 in an effort to reverse the trend.

But out in the shimmering heat of arid Africa, where tens of millions of farmers scratch a living from the soil, new research suggests that this apocalyptic vision is little more than a mirage. Farmers are finding ways to intensify their farming methods without destroying their soils. Farm yields are often up, not down. Soils are often getting better, not worse. Fast-growing populations continue to be fed. In places the desert sands are even retreating. Indeed, for most places at most times, the whole notion of desertification increasingly looks like a myth.

Consider the dusty desert margins of northern Nigeria around the ancient caravan city of Kano, for example. Here, population density has soared to levels similar to Belgium, and some 85 per cent of the land is now cultivated. Rainfall is declining, the availability of chemical fertiliser has fallen by 80 per cent, and only the richest farmers can afford high-yielding grain varieties or irrigation. The poor make do with small scraps of sandy soils. Surely these fields should be turning to desert dust as yields plummet, hunger spreads and refugees head for the cities?

But that’s not what I saw when agricultural scientist BB Singh, who heads the Kano office of the International Institute of Tropical Agriculture, drove me through the area this summer. The dusty roadsides between the closely spaced villages were busy with fruit and vegetable stalls and behind them the fields were already green with bushes laden with the first cowpeas.

Under the burning sun, we visited Ado, a farmer who tends a 2-hectare plot on the outskirts of Badume village, 50 kilometres northwest of Kano. Ado was exultant. The previous year, he had harvested just two bags of cowpeas from his plot. This year, he got seven bags for the same effort. He took me behind the high mud walls of his compound to an inner sanctum where the reasons for his success were bleating. He used to let his sheep roam free. Now he had half a dozen of the animals tethered in his backyard, munching away at straw left over from his fields and creating a large pile of manure for fertiliser. The last mound of muck had been shifted just a few days before to fertilise the next cowpea crop.

Sheep manure is transforming Ado’s life. “Now I can send my three children to school,” he said. “The boys will become farmers, but I want my daughter to become a doctor.” His neighbour Galadima was doing the same thing on his six hectares. “Crops grow much better with manure,” he told me. “I don’t use chemical fertiliser at all now that I have manure.” His two wives and 18 children came running out of the house and lined up for a family photo. They all looked well fed.

Singh’s researchers are monitoring the effects of sheep manure in Badume, and he confirms Ado’s interpretation of his success. But there’s another reason for Ado’s progress, Singh adds-planting leguminous crops such as cowpeas, which fix nitrogen from the air and deposit it in the soil. Frances Harris, a soil scientist at Kingston University in Surrey, agrees that these two strategies work. “The zone has supported intensive cultivation for many years without suffering from land degradation,” she says. “The key is the integration of crops and livestock, because it enhances nutrient cycling.” Legumes and manure put back what the grain crops take out.

As a result, the Kano region is the most agriculturally productive part of the country and farm yields of sorghum, millet, cowpeas and groundnuts are growing rather than dwindling. All this in a region where many experts believe only irrigation can produce worthwhile crop yields. Back in his small office in a back street of Kano, Singh is adamantly optimistic. “Even less than 300 millimetres of rain is enough for good crops. We can double yields here easily and improve the environment at the same time. And this is nothing unusual. We can do it all over Africa.”

Harris makes another point-far from being a liability, the high local population densities are actually essential to this form of intensified farming. In a land where tractors are rare, people provide the labour to tend fields, feed animals and spread manure. The old environmental shibboleth that rising populations trigger soil abuse and desertification is being turned on its head here. As is the idea that livestock are an environmental curse. Far from it, livestock can be an ally of better farming.

All this would be a mere curiosity if the Kano story was a one-off. But similar stories are emerging from all along the Sahara’s edge, from Niger and Senegal, Burkina Faso and Kenya. David Niemeijer, an environmental geographer from Wageningen University in the Netherlands, has spent the past seven years studying the soils of eastern Burkina Faso. “I went there expecting to find widespread land degradation, especially in the most densely populated areas,” he says. After all, the area had seen a decline in rainfall and a tripling of population over 40 years. “But there was no evidence of land degradation connected to human activities. Nor was there any decline in farm productivity. In fact yields of many crops had risen sharply.”

Rice and maize yields per hectare have tripled and sorghum, millet and groundnuts doubled, says Niemeijer. And when he compared soil fertility today with data collected during a French survey in the late 1960s, he found no evidence of declining nutrients. He looked at changes in four different nutrients-nitrogen, carbon, phosphorus and potassium-on five different soil types. In 14 of the 20 comparisons, there was no significant change from the 1960s data. Of the remaining six, four showed an improvement and two a marginal decline in nitrogen. Phosphorus levels were actually higher in cultivated soils than in fallow land. The results were the same for areas with high and low population densities. Almost all the variation in farm yields, it turned out, was down to rainfall.

So, what are farmers doing right? This is no high-tech breakthrough, nor a result of Western aid programmes. Farming methods remain mostly traditional, with few chemical inputs. Niemeijer’s colleague, social scientist Valentina Mazuccato, asked the farmers their secret. “They do not need to invent new management systems as land becomes more limited. All they do is apply some of these soil and water conservation practices more intensively,” says Mazuccato. They erect low walls of stone and earth to keep soil from washing off sloping land in the occasional heavy downpours. They spend more time weeding and thinning crops to improve yields without depleting soils. But above all, they intensify their systems of cooperation, forming gangs to tend each others’ field during busy times, and lending and borrowing land, livestock and farm equipment. They swap seed varieties assiduously.

Whatever they are doing, it’s working. Burkina Faso produced 36 per cent more food in 1998 than it did just eight years earlier, and per capita food production is 20 per cent higher than in 1970. “I am optimistic,” says Niemeijer. “Of course life remains hard. These farmers are still never sure if they can feed their family, and they are not always in control of their destinies. But things are not going down the drain.”

If farmers can maintain soils as they intensify production, can they also use such techniques to rescue their land once it has begun a slide into desertification? The evidence is that they can. Boubacar Yamba of the University of Abdou Moumouni in Niamey, Niger, says that 20 years ago the Maradi district in southern Niger was facing environmental crisis after repeated droughts. Average rainfall was down 30 per cent, the population had doubled in 25 years, soils were crumbling and the last forests were being cut down. Yet, though the rains have never returned to former levels, the millet farmers have fought back, diversifying into growing vegetables, trees and nuts and tending livestock. Desertification has gone into reverse.

But perhaps the best researched example comes from Kenya. Sixty years ago, British colonial scientists wrote off the eroding, treeless hillsides of the drought-prone Machakos district of Kenya, east of Nairobi. Soil inspector Colin Mather called those bare hills “an appalling example” of environmental degradation. The local Akamba people, he said, “are rapidly drifting to a state of hopeless and miserable poverty and their land to a parched desert of rocks, stones and sand”. Similar reports came in the 1950s and again in the 1970s.

There have certainly been bad times, such as last year when the rains failed altogether. But, even though Machakos’s population has risen a staggering fivefold since the 1930s, most years these hills are greener, less eroded and far more productive today than before. Farm output per hectare is ten times what it was in the 1930s and five times what it was in the 1960s. There are, on average, 34 trees per hectare, more than for a century or more. And with tens of thousands of kilometres of terraces dug on steep hillsides, erosion rates are probably also at an all-time low.

What are they doing right? According to Michael Mortimore, a British geographer with long experience in Africa who has written a book on Machakos, the Akamba responded to the environmental crisis by switching from herding cattle to settled farming. This gave them the incentive-and their rising population gave them the labour-to work the land properly, digging terraces and collecting water in ponds for irrigation and weed control.

Every farmer seems to have his or her own story of innovation. On the road out of Machakos town, for example, I dropped in on Jane Ngei, who used an ox plough, spade and wheelbarrow to dig her own small dam to collect rainwater running down the road past her farm. With bucket and perforated hose, she uses the water to irrigate a couple of hectares of vegetables, maize and fruit trees that she grows beside her fields. The Akamba farmers are reaping the rewards of improvements like these, selling vegetables and milk to Nairobi, mangoes and oranges to the Middle East, green beans to Britain and avocados to France.

Machakos district, recently renamed Makueni, is just a couple of hours drive from Nairobi, home of the UN Environment Programme, which still maps much of the district as on the verge of desertification. Yet, strangely, it has never sent anyone to research the reality. UNEP’s Timo Maukonen says he believes the main reason for the Machakos success story is the proximity of a large market, Nairobi, for the farmers’ produce. Tom Slaymaker of Britain’s Overseas Development Institute agrees. He stands by his claim in a recent study that “there are few examples of reversal of natural resource degradation and no evidence of a wider trend of environmental recovery.” He insists that “successful cases seem to be rather isolated.”

But other experts are taking a more cautious line and question the value of sweeping claims of environmental decline made by UNEP and other UN agencies. Camilla Toulmin, head of the drylands programme of the International Institute for Environment and Development in London and a leading drafter of the Desertification Convention, admits that “evidence for soil fertility decline stems from a few highly influential studies of land degradation in Africa, which have been quoted over and over again, in the process often losing much of the qualification surrounding the original study.” Much of it, she says, doesn’t stand up to detailed investigation on the ground. “Detailed field-level studies demonstrate that the soil fertility problem is far more complex and diverse.”

One problem has been that researchers tend to visit such areas so rarely that they have little history to back up their guesses about environmental processes. Land that appears “degraded”-that is, highly eroded-may have been that way long before the arrival of farming or grazing. “Every piece of degraded land has been seen as evidence of destructive human activity,” says Niemeijer. “But when we asked farmers about areas of degraded land near their villages, they generally said it had been there a long time and was a natural feature. And in some cases they were starting to reclaim these areas for farming.”

Deserts did advance in Africa during the droughts of the 1970s and 1980s. The conventional view at the time was that farmers, at least as much as drought, were to blame, and that the processes were irreversible. But even when, in the early 1990s, satellite images began to show the Sahara retreating during years of higher rainfall, the image of desertification caused by human activity stuck. It became what Mortimore calls an “institutional fact”, too important for careers and reputations to be lightly dropped. And it is only now that detailed evidence of what has happened to soils and farm productivity in these supposedly doomed regions is finally emerging. The myth of traditional African farmers as both environmental villains and victims is finally being exposed.

The truth is not that farmers never destroy soils, nor that deserts never advance, but that there is nothing inevitable about the process-it may be the exception rather than the rule. And even when soils have been in decline, as in Machakos, farmers have shown themselves quite capable of turning the tide. Moreover, it seems that even the rapid growth of population in many African countries can be a spur to change, rather than a curse. As Singh puts it: “There is no reason why Africa cannot feed itself.”

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