Africa is rich in both natural and human resources, yet nearly 200 million of its people are undernourished because of inadequate food supplies. Comprehensive strategies are needed across the continent to harness the power of science and technology (S&T) in ways that boost agricultural productivity, profitability, and sustainability -- ultimately ensuring that all Africans have access to enough safe and nutritious food to meet their dietary needs. This report addresses the question of how science and technology can be mobilized to make that promise a reality.
Diversity is the norm in African farming systems. Even at the level of the individual farm unit, farmers typically cultivate 10 or more crops in diverse mixtures that vary across soil type, topographical position and distance from the household compound. Dixon and colleagues (2001) provide the most comprehensive description of farming systems globally (Table 3.1 and Figure 3.1). They identify and broadly delimit farming systems based on the (a) natural resource base; (b) dominant livelihoods (main staple and cash income source - a balance between crops, livestock, fishing, forestry and off-farm activities); (c) degree of crop-livestock integration and (d) scale of operation. The main characteristics of the major farming systems in Africa are shown in Table 3.1. Analysis of various systems has shown that mixed cropping systems reduce risk, reduce crop losses from pests and diseases and make more efficient use of farm labour. Science and technology (S&T) investments are embodied in these systems' commodities and resource management practices in often complex and interdependent ways.
Farming systems in Sub-Saharan Africa comprise many root crops, especially cassava. Cereals are less important. The main crops are coarsegrains like millet and sorghum, followed by maize. The International Model for Policy Analysis of Agricutural Commodities and Trade (IMPACT) developed by the International Food Policy Research Institute (IFPRI) to project the future demand for these commodities, estimated that the per capita demand for cereal crops will increase in Sub-Saharan Africa by some 4.9 percent per year between 1997 and 2020, with the main increase in wheat and rice (Rosegrant et al., 2001). Part of the increase will be due to greater demand for animal feed. The demand for root and tuber crops will increase by about 65 percent, more or less evenly spread over all species.
The farming systems described provide a snapshot of dynamic systems that are constantly evolving. Both endogenous factors (household goals, labour, technologies in use and the resource base) and exogenous factors (market development, shifts in demand, agricultural services and policies, the dissemination of new technologies and the availability of market and policy information) drive the evolution of individual farms and, collectively, the overall farming system.
Farming systems may evolve along several pathways. Population growth combined with new technology options and/or market opportunities can induce farmers to diversify and intensify systems. Depending on the natural resource base and management systems, intensification can either sustain and improve productivity over time, or degrade the natural resource base and therefore lower production potential over time. On the other hand, population growth in the absence of technological or market opportunities can lead to deepening poverty, degradation of the resource base and long-term agricultural involution.
Over decades, farming systems may differentiate into subtypes that continue to evolve along different pathways. For example, in systems under population and market pressure, some farms may successfully intensify and even specialize to produce for the market, whereas others may regress to low-input/low-output systems. Moreover, in any one location within a farming system, different farms are likely to be at different stages of evolution because of differentiated resource bases, household goals, capacity to bear risk or degree of market access. Individual farm systems may also be shifted out of the overall trajectory of system evolution because of shocks - internal (such as family sickness), external (natural disasters) or policy (such as structural adjustment).
Livestock are an integral part of the agricultural systems of Africa and especially important to the poor (Box 3.1), who derive a larger proportion of their meagre incomes from livestock than do the wealthier (Delgado et al., 1999).
Perry and colleagues (2002) discuss the importance of livestock in African farming systems at length. They define animal production systems according to their major characteristics and agro-ecological zoning (Table 3.2). Further, they differentiate between these systems in West Africa and in Eastern/Central/Southern Africa.
In the mixed crop-livestock systems of the arid/semi-arid (MRA), humid/subhumid (MRH) and tropical highlands (MRT) of Eastern, Central and Southern Africa, cattle are judged of greatest importance to the poor, followed by sheep and goats, poultry, horses, donkeys and mules, with pigs last. By contrast in the same systems in West Africa, sheep and goats rank highest, followed by poultry and cattle, then horses, donkeys and mules, with pigs again last. In the pastoral rangeland-based systems in Africa, sheep and goats are generally regarded as of highest relevance to the poor, followed by cattle, camels and horses, donkeys and mules.
In Sub-Saharan Africa the total output of animal products is worth most in the pastoral rangeland-based systems in the arid/semi-arid region (LGA), followed by the mixed rainfed crop-livestock systems in the humid/subhumid tropics (MRH) and then the mixed rainfed crop-livestock systems in the arid/semi-arid tropics (MRA) (ILRI 2000). However there are more than twice as many poor people dependent on the mixed rainfed crop-livestock systems in the humid/subhumid tropics (MRH) than depend on the other two systems. In West Asia/North Africa by far the most economically important livestock production system is the mixed rainfed crop-livestock system in the arid/semi-arid tropics (MRA). However it supports less than one-third of the numbers of poor people than are supported by the humid/subhumid system in Sub-Saharan Africa. More than 60 percent of the poor in West Asia/North Africa are in West Asia (Thornton et al., 2002).
The three mixed rainfed crop-livestock systems (MRA, RMH and MRT) represent more than 70 percent of the estimated 280 million poor people in Sub-Saharan Africa (Thornton et al., 2002). The pastoral rangeland-based systems support around 10 percent. In North Africa the mixed irrigated arid/semi-arid crop-livestock system (MIA) comprises 44 percent of the total poor in the region, while the three mixed rainfed crop-livestock systems represent only 25 percent.
Demand for meat and milk is projected to more than double over the next two decades in developing countries. The major factors driving this rising demand are population growth, increased urbanization and higher incomes. Sub-Saharan Africa is projected to have the greatest annual growth in consumption of meat (3.5 percent) of any other region and the second highest growth of milk consumption (3.8 percent). These far exceed growth projections in demand for foodgrains. Because livestock are an important livelihood asset for the poor in Africa, this 'Livestock Revolution' (Delgado et al., 1999) has the potential to provide a platform for the poor in Africa to reap a disproportionate share of the benefits of this demand growth.
If livestock production is to keep pace with demand the imperative is to enhance productivity per animal and reduce wastage. In Sub-Saharan Africa, recent productivity growth per animal has been far less than the projected growth rates of demand for all species. Productivity growth has ranged from -0.5 to 0.6 percent per year while demand growth is projected to be between 2.6 and 4.2 percent per year (ILRI, 2000). In West Asia/North Africa the demand - productivity growth gap is not nearly as large as in Sub-Saharan Africa.