干旱区生态环境知识资源中心

In the semi-arid and and regions of Northern Africa and the Middle East pastoralism was the traditional and most widespread land-use system. Nomads in the Middle East and all over the world are under increasing pressure to lead a more sedentary way of life. In order to allow this inevitable change, a transition phase is necessary in which nomads are able to secure their own livelihood without having to give up their cultural heritage and traditions. A combination of runoff-water harvesting and agroforestry techniques (known as 'runoff agroforestry systems' or 'RAS') has recently been proposed as a system that allows the simultaneous production of food, fodder and firewood. This system could meet the needs of pastoralists without exploiting large tracts of land. This approach was tested in 1994 near the town of Kakuma in the Turkana region of Kenya. Various tree/crop management strategies were tested in a system in which Sorghum bicolor (L.) Moench was the intercrop and Acacia saligna (Labill.) H. L. Wendl was the tree component. Tree planting density, tree pruning and intercropping were tested. Biomass yields and productivity per unit of land were the highest when trees were pruned and intercropped. Runoff agroforestry is less affected by inter-annual rainfall variability than rain-fed systems, and supports the natural regeneration of degraded rangeland. (C) 2003 Elsevier Science Ltd.