ficiency through specialization. This is particularly so where roads and railways reduce transportation costs and open new markets and where harbors and airports create opportunities for exports and contribute to lowering the costs of imported agricultural inputs (Estache et al., 2005). Subsistence agriculture is least affected because it uses few external inputs and the produce is consumed locally. Although literature on the link between transport and poverty is fairly substantial, there is little on the link between transportation infrastructure and AKST. Effective transportation infrastructure is generally associated with greater agricultural output, higher incomes, better indicators of access to health services and greater wage income opportunities. The effect of road infrastructure on poverty alleviation is positive and significant, partly because of the effect on market access and on agricultural and rural development (Bhattarai and Narayanamoorthy, 2003).

Transportation infrastructure in most SSA countries is generally underdeveloped and in some places underused. This is partly attributed to the fact that transportation infrastructure, although important, is expensive to build and maintain, difficult to manage and easy to abuse, mainly by overloading vehicles (Farrington and Gill, 2002). SSA has an estimated 1.8 million km of roads, of which only 16% are paved. Rail, marine and air freight are low, making up less than 2%, 11% and 1%, respectively, of the world’s totals. Marine transport is rare since 90% of Africa’s land and 80% of its populated area lies more than 100 km from the coast, lake or a navigable river. In some cases, where transportation infrastructure is built for broad commercial objectives, builders have failed to take into account the special needs of specific subsectors such as fisheries, livestock and forestry. While many airports have sufficient runway capacity to handle large cargo planes, limited trade volumes and inadequate cold storage facilities hinder the export of high-value perishables (NEPAD, 2002).           Inadequate and ineffective transportation infrastructure constrains investment and market integration in rural areas, mainly because of the high cost of transportation. Landlocked countries pay high prices for imports and get low prices for their exports. For example, importers in the Central African Republic and Chad pay cost, insurance and freight (CIF) prices that are 1.3 to 1.8 times the cost of the products when they leave the exporting countries, while their coffee is 2.8 times the production cost when it arrives in Europe. The main economic reason for inadequate fertilizer input in SSA is poor transportation infrastructure (Sanchez and Swaminathan, 2005). In Burkina Faso, Uganda, and Zambia walking is the principal means of transportation for 87% of rural residents (Torero and Chowdhury, 2004). This affects labor productivity and indirectly constrains agricultural development.

Some agricultural areas are well connected to markets, particularly the major food and cash crop-producing areas. In Kenya, export horticultural produce is grown in areas with good road infrastructure and the government gives priority to improving roads in the main food and cash cropproducing areas (Kenya Ministry of Agriculture, 2004). Location and climate greatly affect income levels and income growth, causing differences in transportation costs, health and agricultural productivity (Gallup et al., 1998). There

is linear correlation between GDP and road infrastructure (Estache et al., 2005). In relatively wealthy SSA countries such as South Africa, Namibia and Botswana, most highpotential agricultural areas are well linked to the market, whereas in poorer countries like Burkina Faso, Eritrea and Chad, most of the areas with high agricultural potential are
poorly linked. In general, many parts of poorer SSA countries with agricultural potential are not exploited because of the absence or poor state of transportation infrastructure. In the two leading milk-producing districts in Kenya, milk waste is 30%, mainly because of the difficulties in getting milk to the market or processing plant in time, particularly during rainy seasons (Neondo, 2002).

Where transportation infrastructure is effective, an increase in agricultural yields of one-third might reduce the number of poor by 25% or more (Irz et al., 2001; Farrington and Gill, 2002; Mellor and Ranade, 2002). Consensus is growing that providing adequate infrastructure for transportation is an important step toward alleviating poverty and providing equitable opportunities for rural citizens by linking small-scale producers to markets and reducing the market risk and transaction costs they face.

3.3.2.2 Water and energy
Infrastructure for agricultural water management is required to facilitate agricultural expansion and intensification in semiarid and arid areas (irrigation infrastructure), to remove excess water (drainage infrastructure), to support intensification of rainfed agriculture (water-harvesting infrastructure) and to encourage recycling and reuse. Water
storage is required to reduce the mismatch between water supply and demand and to protect downstream agriculture in floodplains from flood damage. To avert the emerging water crisis in many parts of SSA, additional water storage needs range from 751 m3 person-1 in Lesotho to 152 m3 person- 1 in Burkina Faso (Grey, 2004).

Small reservoirs reduce climate risk, facilitate adoption of higher-yielding crop varieties, increase appropriate fertilizer use, and make possible better crop, soil and water management practices (Faulkner, 2006). These improvements lead to greater resource efficiency, a 40-160% increase in maize yield and a 30-85% increase in profitability. Irrigation potential is largely unexploited, partly because of inadequate water storage and the high cost of irrigation infrastructure (FAO, 1995, 2005). Small reservoirs in northern Ghana and southern Burkina Faso have played a critical role in improving agricultural output and enhancing food security (Andreini et al., 2000). Ongoing research that is part of the CGIAR Challenge Program is intended to optimize benefits in the community by developing small reservoirs and reducing the negative effects arising through overuse of water in the upper reaches of rivers (Andreini et al., 2005).

Development of high-yielding varieties and the need to increase agricultural outputs in semiarid and arid areas have been the major drivers of irrigation development. Irrigation in turn has led to increased access to and adaptation, adoption and effectiveness of AKST. The full range of irrigation development options should be critically examined so that the best choices are made to suit the type of farmers, farming system and agroclimatic zones.

Sixty percent of the primary energy supply in SSA is