Soil and Nutrients

Africa's soils are too poor to meet the needs of its rapidly growing population. Soil mining - the removal of nutrients by crops without replenishment - is making the situation worse. Land degradation, especially resulting from soil nutrient depletion and erosion, is the major factor responsible for stagnant and low yields.

About 900 million hectares of Africa's land is considered suitable for agricultural production but about 83 percent of this has serious soil fertility or other limitations. Africa loses an estimated USD 4 billion worth of plant nutrients every year, eroding its ability to grow its own food. Costly improvements are needed to achieve high and sustained productivity.

Three-quarters of the farmland in sub-Saharan Africa is plagued by severe nutrient depletion, and 46% of the African continent suffers from desertification. Meanwhile, fertilizer application rates in African remain very low - on average, one-fifth the rate in Latin America and one-twelfth the level in Asia.

No single technology can restore soil fertility and improve soil productivity, but there is a range of proven technological options to apply:

• increased and improved use of mineral fertilizers
• use of locally available fertilizer materials, e.g. phosphate rock, lime, dolomite and gypsum
• increased recycling of organic products
• promotion of integrated plant nutrition systems
• mobilization of additional nutrient resources through organic recycling
• promotion of biological nitrogen fixation (BNF), inoculant production and quality control

Consistent and long-term policies and strategies are necessary to reverse the situation. Average fertilizer nutrient application rates in sub-Saharan Africa need an annual growth rate of 2.5 percent to prevent continuous mining of plant nutrients and low productivity. This growth rate is within a reasonable range of historically observed levels in Africa (e.g. Egypt and Morocco) and other parts of the world.

Future donors could help to ensure that developing countries have meaningful, stable and rational fertilizer policies. The first step of the fertilizer challenge will be the creation of effective demand, primarily by improving fertilizer-use profitability.

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