Some aspects of dry land afforestation in the Sudan with special reference to Acacia tortilis (Forsk.) Hayne, A. senegal Willd. and Prosopis chilensis (Molina) stuntz

Arid lands in the Sudan have been subjected to degradation manifested by loss of soil fertility, shortages of fodder and fuel, and moving sands. Acacia tortilis, (Forsk.) Hayne, A. senegal Willd. and Prosopis chilensis (Molina) Stuntz are valuable afforestation species to restore these lands and provide fodder, fuelwood and other products. Animals, particularly goats and sheep, are effective long-distance dispersers of seeds of A. tortilis and P. chilensis. The ingested seeds are preserved from further attacks of predators particularly bruchids, and their germination capabilities are enhanced by ingestion and pelleting. Because of the small mass of the droppings, the ingested seeds are transported by wind and water to low-lying places where run-off water collects (favourable sites). As rainfall fluctuations are common, natural regeneration, using seeds in animal droppings and using only favourable sites in the semidesert tract, is recommended. The trees established on such sites can form focal points from which the trees can further spread through animals feeding on their pods. Soil working in the form of saucer-pits, ridges and furrows was successful in establishing P. chilensis in arid lands.

Afforestation by seeding A. senegal using agricultural machinery in farms abandoned because of loss of soil fertility was successful in the central clay plains of the Sudan as weed growth was not intense and the seeds are cheap.