A technique using small amounts of fertiliser, pioneered by African agricultural scientists, is boosting crop yields in degraded soils.
According to the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), 25,000 farm families in Burkina Faso, Mali and Niger have significantly improved yields of sorghum, maize and millet by adding just a ''three-finger pinch'' (six grams) of fertiliser when planting seeds or within three weeks of sowing.
This revitalises areas suffering degraded soil and empowers farmers in areas where fertiliser is difficult to obtain or too expensive, says Ramadjita Tabo, ICRISAT's assistant director for West and Central Africa.
Dubbed 'microdosing', the technique arose through five years of research by soil scientist André Bationo at the International Centre for Soil Fertility and ICRISAT's Desert Margins Programme, together with researchers at the Institute of Agronomic Research and the Inputs Project of the UN Food and Agriculture Organization in Niger.
The technique and type of fertiliser varies depending on the soil and climate. For example, in hard soil farmers dig small holes and fill it with manure before the rains begin, then apply fertiliser and plant when rains begin, to provide an optimal moist environment for the crop and prevent run off of the chemicals into the hard soil.
Small quantities of high-phosphorus fertiliser tablets were distributed to farmers for pilot studies in farms in Mali, with monitoring help from Sako Karamoko from the European Cooperative for Rural Development (EUCORD) and Sandinan Boubacar from Sasakawa Global 2000, a Japanese-funded agricultural research project.
Particular effort was put into implementing the research. Jean-Baptiste Sibiry Taonda from the Environmental and Agricultural Research Institute in Burkina Faso was closely involved in disseminating the research findings and technology to farmers, with the help of agricultural extension officers.
ICRISAT and its partners are also working with fertiliser companies to sell smaller packs of fertiliser in villages, persuading them that small quantities are better than no sales at all.
Plans are now being made to use fertiliser tablets and scale-up mechanical seeding technology, to make the technique less labour intensive — the fastest method uses two people, one to make the hole and the other to plant the seeds and apply the fertiliser.
''We would like to scale up to reach up to half a million farmers in West, East and Southern Africa,'' Tabo told SciDev.Net.
Microdosing field trials are also being conducted in Niger on groundnuts, cowpeas, okra, tomato and other vegetables. Tabo says the full results are not expected for three years.
Progress will be discussed at the Challenge Programme on Water and Food workshop in Tamale in Ghana in September and the Second International Forum on Water and Food in Addis Ababa, Ethiopia, in November.