The Role of Indigenous Fruit Trees in Sustainable Dryland Agriculture in Eastern Africa - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 216

threat to the livelihood and well-being of people in the region (IPED, 1994;
Akhtar-Schuster et al ., 2000; Darkoh, 2003). Unless the degradation process is
reversed and a more environmentally sound agricultural system is adopted, the
economic and social factors that are driving the degradation of the ecosystem
are likely to exert further pressure on dryland agriculture. Since the functioning
and sustainability of dryland agriculture depend greatly on trees, as described
above, the domestication and management of indigenous fruit trees in the form
of the traditional agroforestry parkland system may be a solution.
11.4 Challenges and Strategies for Improvement
Traditional dryland agriculture used to be sustainable when population density
was low. But the rapidly increasing population is now leading to land degradation
and desertification in many areas of Eastern Africa. Dryland agriculture in
Eastern Africa is losing soil fertility and biodiversity largely as a result of rising
population pressure and an uncertain water supply because of frequent droughts.
Traditional methods of agriculture and animal husbandry are therefore becoming
difficult to sustain and new methods or approaches are needed to address the
increasing pressure on natural resources. Making dryland agriculture sustainable
is the greatest challenge facing the world today. There are very few answers to
this as the problems of drylands are many and complex. The two major
constraints on dryland agriculture are water availability, which limits crop yield
almost every year, and loss of soil fertility in excess of the soil's natural rate of
formation, as a result of either soil erosion or the shortening of fallow periods
(Grouzis and Akpo, 1997). The priority indigenous tree species discussed above
have the potential to restore the ecosystem functions of drylands by overcoming
at least these two major constraints. The judicious planting of these trees in the
form of agroforestry parkland systems can improve the sustainability and
productivity of dryland agriculture because trees are capable of increasing the
efficiency of water and nutrient use in the systems, thereby increasing associated
crop production, as described in Section 11.3.3 of this chapter. These trees are
well suited to farmers because they are the most preferred species locally. The
trees are also capable of improving the nutritional status of societies as their fruits
contain high levels of energy, protein, fat, vitamins and minerals, as discussed in
Section 11.3.2. Therefore, by domesticating and cultivating the priority
indigenous trees on farms, it will be possible to achieve food security, higher
export earnings and sustainable and productive dryland agriculture. This
approach is also attractive financially because of the low cash inputs needed and
generally higher returns to land and labour. In order to achieve successful
domestication and cultivation of indigenous fruit trees and to ensure that they
play their role in sustaining dryland agriculture, the following strategies are
deemed necessary.