A $180m (£90m) five-year project to revive sub-Saharan Africa's depleted soils has been launched in Nairobi.

The programme will give particular attention to women, who make up the majority of small-scale farmers, who are best placed to know how various crops fare in local soils, explained Dr Akin Adesina, AGRA's vice president for policy and partnerships.

Unsustainable practices in recent decades had led to soil degradation in the region. For example, continuous cultivation of land without replacing nutrients taken up by crops had led to a fall in soil fertility.

Degraded soils were also prone to erosion and were unable to retain moisture.

Researchers said the poor conditions meant that farmers were more likely to clear forests and savannahs as they searched for arable land.

http://news.bbc.co.uk/2/hi/science/nature/7209608.stm

How would they replenish the soil?

How would they replenish the soil?Well geeze Sam, you're the biologist so we should be asking you that. I presume that it's just a large-scale version of what you do to your lawn if it starts to look crappy after a decade or two without composting or crop rotation. Saturate it with chemically manufactured fertilizer. The people who foisted Windows on us, which threatens to destroy civilization with its wretched quality and abysmal security, are going to give some of the billions of dollars they earned from Windows to an American corporation that makes chemical fertilizer. Then they ship the fertilizer to Africa. Sounds like the same kind of economic incest we had in the 1960s and early 1970s, when the out-of-control government threw our tax money at weapons manufacturers and then threw the weapons at Vietnam.

No one is going to actually set up an organization in Africa whose goal will be to help Africans develop a sustainable economy. African nations should be building Industrial Era factories like China; their people could live like princes on three dollars a day and import their food. The food should be grown in the Americas. Our continents are sparsely populated and have plenty of good-quality soil, much of which has been well tended and rotated so it doesn't require chemical treatment. South America could feed the world, Africa could build the world's widgets, and everybody would prosper.

Maybe the Gates family should consider using its money to support a software research foundation, whose mission would be to develop software that makes sense to people who don't think like programmers.

Fraggle:

I was wondering since they did not think fit to mention it.

From my ancient classes on ecology, I recall that the methods used traditionally were some variation of nitrogen fixation and biological replenishment attained mostly by cycling crops and leaving the ground fallow for some time.

Looking up this issue, I located the following information.

Replenishing Soil Fertility in Africa (http://www.worldagroforestry.org/units/library/books/pdfs/91_Replenishing_soil_fertility_in_africa.pdf)
Readers will survey the challenges of decreasing per-capita food production in Sub-Saharan Africa with a multidisciplinary team of soil scientists, agronomists, economists, anthropologists, and foresters. The book begins with the conceptual approach of investing in natural resource capital, followed by an analysis of the magnitude of soil depletion, a review of field research, an NGO approach, and a perspective from temperate-region soils. Three process-oriented chapters treat phosphorus, nitrogen, and organic and inorganic nutrient inputs, and two chapters focus on key socieconomic considerations.

So, it would appear that its much more complex than dumping fertiliser.

Soil Fertility and Hunger in Africa (http://www.sciencemag.org/cgi/content/summary/295/5562/2019?siteid=sci&ijkey=EMQmOjsSVVbg6&keytype=ref)
Also, it would appear that chemical fertilisers are too expensive for the average farmer and natural solutions are being pursued.

Because mineral fertilizers cost two to six times as much as those sold worldwide, a soil fertility replenishment approach has been developed based on naturally available resources: nitrogen-fixing leguminous tree fallows that accumulate 100 to 200 kg N ha-1, indigenous rock phosphate applications, and biomass transfers of the nutrient-accumulating shrub Tithonia diversifolia. Tens of thousands of farmers in East and Southern Africa are becoming food secure with these technologies. Soil fertility depletion must be addressed before other technologies and policies can become effective in overcoming hunger in Africa.



However there are other issues, like soil mining, or borrowing the fertility of one soil to pay it back later, which need to be addressed, as poor economic conditions can make it difficult for farmers to sustain their farms over a long period.

Farmer interviews have shown that they recognize the depletion that is occurring in their outer fields and will correct when it is affordable and remunerative to do so (Scoones 2001; Tiffen 2002). Rural dwellers also shift their village locations over time, altering the positioning of homestead fields versus outer fields. These adaptive responses suggest that farmers are 'borrowing' soil fertility from one area and lending to another, to be paid back later when they are able. But will this ever happen?

As markets develop, for example farmers gain the economic capacity to buy more fertilizer and invest in larger areas of farmland. Farmers also change crops in response to market signals and soil fertility conditions. Thirdly, they seek off-farm employment and send remittances back to the farm-which can include investments in soil fertility such as fertilizer, when economic conditions favor the investment (e.g. for high-value crops).

Viewed in this dynamic context, static estimates of continental nutrient balances from simple experimental plots seem too coarse a tool upon which to interpret farmer behavior or to formulate research, development and policy directions, according to the dissenting scientists.

A fertility borrowing perspective implies a different set of research and development imperatives. Research is needed to evaluate the capacity, resilience, and balance dynamics of these resource pools. How long can the borrowing go on without permanent damage to the outfield and grazing land resources? How can farmers be assisted in their natural inclination to rehabilitate these areas? The fertility borrowing concept highlights the opportunity to build on farmers' responsiveness to markets by introducing infrastructure, policy reform, and technology interventions that reduce the costs of, and increase the rewards from fertilizer use.



There are many approaches possible, all awaiting the human factor of compassionate intervention.

Another factor which I thought interesting was the gender differences in farm production:

women farmers usually produce the subsistence food crops, while men produce export and cash crops. African women on small rainfed farms produce up to 70-80% of the domestic food supply in most sub-Saharan African societies and also provide 46% of the agricultural labor. However, women's food-crop yields are generally low -- too low by Green Revolution standards, and much lower than men's yields. The papers collected here examine different projects in Africa with respect to the different methods used to reach women farmers in order to improve their soils and increase their yields. Such methods include fertilizer vouchers and grants, microcredit, small bags of fertilizer, agroforestry and legume innovations, and increased cash cropping by women. Results demonstrate to African policy makers which methods work, and reach women farmers with different household compositions, so that they can reverse the alarming trend toward declining per capita food production.
http://web.africa.ufl.edu/asq/v6/v6i1a1.htm

Well, we need to be careful here, and perhaps heed the cry of an increasing number of Africans:

Please leave us alone! You have been meddling in our affairs for more than a thousand years. What you see is what YOU have accomplished, with your occupations, your religious missionaries, your slave trade, your wars, your colonial administrators, your vaccines, your military alliances, your schools, your churches, your hospitals, your commerce, your agricultural breakthroughs... even your Peace Corps. You have to let us find our own way.

Fraggle:

Africa can't afford chemical fertilizers. Not even in Kenya where they tend to be more affluent than other african countries. (And assuming the current violence doesn't destroy the nation.)

As for our soil being so well tended that it doesn't require additional fertilizer, well, that's a crock. We HAVE to add nitrogen compounds and other materials to maintain the yeild of farmland. We're getting smarter, and can just about balance the removal of minerals from forage cropland with liquified animal wastes, but it still requires occasional addition of other materials to balance out.

Ammonia/ Nitrogen based fertilizer usually come from China, India and Pakistan and cheap to buy. Phosphate based comes from Senegal, No survey is done for Potasium based salt in Africa. Sulphur based products are everywhere.

Africa also has gas deposits in Nigeria, Cameroon, Uganda etc. that can be converted to Ammonium Salts and Urea.

The real problem in African farmlands is that the production process is not mechanized and so highly inefficient.

The food should be grown in the Americas. Our continents are sparsely populated and have plenty of good-quality soil, much of which has been well tended and rotated so it doesn't require chemical treatment.

Maybe 100 years ago, gramps, but all our farmland is seriously destroyed. We lose tons upon tons of topsoil every year. The Mississippi clogs up because of the massive run off. But it doesn't matter, because we can afford synthesized fertilizers. In some places in America, nitrate run off is so high babies come out retarded and people get sick. They're poisoning their well water with it.

Farmland in America is absolutely devastated, and has been since the 50s. Maybe if we plowed over some National Park or turned other land into farmland, yeah, we could make enough cheap food to feed Africans.

Of course, we'd already be doing that if it was economically profitable. But because American farmers are extremely inefficient at growing stuff, and because that farmland would be far more valuable as something else, there's no way our crops would be able to compete on a global scale, unless the government really leaned in a propped them up. Which they do already. Hopefully NAFTA will be able to break up some of that crap, but I doubt it.