BioEd Online

African countries must boost the fertility of the soil underfoot if they want to fill empty bellies, said a group of dignitaries gathered in New York City this week.

"Our quest is to nourish Africa's soils and feed the continent," said President Olusegun Obasanjo of Nigeria at a press conference held to draw attention to the continent's barren soil. He is part of an advisory panel who met to launch the Africa Fertilizer Summit, a meeting that will be held in Abuja, Nigeria, from 9-13 June.

Although drought may be the best known barrier to successful crops in Africa, the poor soils are a huge part of the equation. Farmland in Africa has been robbed of chemicals such as nitrogen, phosphorus and potassium, which are vital for plant growth. And these have not been replaced with organic and chemical fertilizers, as they are in most other countries, because of the expense.

The nutrient-starved soils have become one of the major factors preventing the 200 million malnourished people in the continent from growing enough food to eat and sell. "Poor soil fertility is the fundamental cause for low agricultural production in hunger-endemic areas," notes Alfred Hartemink of World Soil Information (ISRIC) in Wageningen, The Netherlands.

Three-quarters degraded

Researchers at the meeting presented a comprehensive report, by Julio Henao and Carlos Baanante of the International Center for Soil Fertility and Agricultural Development (IFDC), that paints a bleak picture of the situation.

In their analysis, the researchers totted up the nutrients that feed the soil, and subtracted losses from leaching, volatilization, erosion and crop uptake. They plugged these numbers, which differ from region to region, into a computer model to come up with a picture for the entire continent over time.

The study showed that around three-quarters of the continent's land is severely degraded of nutrients, with many regions losing as much as 60 kilograms per hectare each year. As a result, the production of cereals in sub-Saharan Africa has stagnated at one tonne per hectare compared with around three tonnes in the rest of the world, the report says.

No easy cure

"Dumping fertilizers alone will not help," warns agricultural scientist Rattan Lal of Ohio State University, Columbus, because most of them will wash away or evaporate from cement-hard, hot ground.

He says that fertilizers can work only in combination with other methods to restore soils, such as planting cover crops that anchor the nutrient-rich topsoil and supply organic matter between crop cycles. "Those are the things that build up the soil's life-support system," Lal says.

Judicious use of chemical fertilizers could also be tremendously useful, the meeting participants said. Any environmental damage from the chemicals must be balanced against the far greater damage being wreaked today by farmers who raze forests in order to find fertile land.

Summer hopes

The June fertilizer summit, convened by the African Union's New Partnership for Africa's Development (NEPAD), will aim to produce a list of actions to nourish soils.

This will include measures to improve the cost and availability of fertilizers, and to help farmers to adopt best practices. Development experts say that this must also be an integral part of broader measures to build up infrastructure such as roads and schools and open up access to local and international markets.

"I'm convinced it will be a turning point in the will of our continent and our countries to take care of itself," said Alpha Oumar Konaré, chairman of the Commission of the African Union.

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