Wider range of crops grow under Sahelian tree
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CTA. 1995. Wider range of crops grow under Sahelian tree. Spore 59. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47161
Research has confirmed that farmers in the Sahel can increase the range and yields of their crops if they plant them under a Faidherbia albida (Acacia albida) tree. This tree has been traditionally conserved in the region, because its benefits have...
Research has confirmed that farmers in the Sahel can increase the range and yields of their crops if they plant them under a Faidherbia albida (Acacia albida) tree. This tree has been traditionally conserved in the region, because its benefits have long been recognized although not quantified. Crops can be grown under the tree because it has a reverse physiology: during the rains it sheds its leaves resulting in plenty of light for crops. At the beginning of the dry season it comes into leaf again and in the hot, dry months it provides welcome shade to livestock, which also like the fruit pods that drop to the ground. Researchers at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Sahelian Centre in Niger have found other benefits. The tree, known locally as the Gao, creates a micro-climate under its branches where it is cooler and there is less radiation. This allows crops such as maize or sorghum to be grown in the region whereas normally these crops can only be grown further south. Another advantage is that fertility is higher under the trees because animals have rested there and leaves have fallen on the soil. Because the Gao has deep roots, there is no competition with the annual crops. The researchers have shown that maize grown under the spread of the tree will yield 1.5 tonnes and sorghum about 1 tonne, compared to 700 kg for millet. However, maize and sorghum planted beyond the spread were both outyielded by millet. A large tree can have a spread of 20 to 25 metres diameter, and in many parts of the Sahel there may be 4 or 5 of these trees per hectare, so the beneficial effect on yield is considerable. The system gives farmers an opportunity to grow a crop that can be sold for cash, without depriving them of their subsistence crop of millet. Researchers at the Sahelian Centre see the system as being sustainable only if farmers continue to rest livestock under the Gao during noncropping periods in order to help maintain soil fertility. ICRISAT, Sahelian Centre B P 12404 Niamey NIGER