Total arable land area of SSA is estimated at 131 million hectares (Table 2). The average per capita land area of 0.27 ha is only slightly lower than the world average of 0.33 ha. However, for the expected population of 1478 million by the year 2025, the per capita land area may be as low as 0.09 ha with no additional land brought under cultivation (Table 2), and 0.18 ha if new land is cleared at the rate of 0.6% per year of the existing rainforest (Lal 1993b).
Sub-Saharan Africa (SSA), is undergoing agrarian stagnation, becoming world famous as a region where natural resources are stressed to the limit and the place where food relief efforts have become routine. Concerns of accelerated erosion, desertification, deforestation and other human-driven destruction phenomena have placed SSA under recurrent threat of starvation and malnutrition. Waterways and reservoirs continue to silt-up as rivers and lakes get polluted. From the agriculture perspective, and when tillage is given the broader meaning of "soil manipulation for any purpose" it is realizable that inappropriate tillage methods remain the major contributors to this trend.
Though loaded with high natural and economic diversity, SSA has 2231 million hectares of land, of which only 6% is arable. Annual rainfall amounts range from zero in the deserts to 5000mm in the highlands and all major soils are present.
Despite various but non-comprehensive efforts put in place at national and regional level ESA gains have been more in terms of economic and political togetherness and less so, by way of communally or regionally arresting environmental degradation. Environment preservation needs to be addressed across the borders as solitary efforts of individual nations simply do not do. It is noteworthy that, in ESA, human capacity is no longer as limiting as a few decades ago. Africa has the human capital needed to develop physical resources. Recent decades have seen the development of manpower with all the skills needed for the broad range of human needs. Technical manpower is especially strong in populous countries, like, Nigeria, Ghana, Kenya and Zimbabwe. In fact, unemployment and under-employment of trained personnel has contributed to mass exodus to European, North America and the Middle East (Lal, 1992).
The greater shortcoming is probably the general sense of environmental sustainability. With the potential adequately exploited, soil resources of Africa are adequate to support an acceptable standard of living for the current and future populations of SSA. FAO (1984) reported (see Table 3) that SSA could support 1120 million people at low levels of input, 4608 million at intermediate levels and 12930 million at high levels of input. The report was written at a time when the SSA population was only 400 million.
Rate of increase : (i) 1986 to 2000, 3.2% yr (ii) 2000 to 2025, 3.2% yr; and (iii) 2025 to 2050, 3.0 % yr.
Table 1: Projected population of sub-Saharan Africa+
This paper is published in: Kaumbutho P G and Simalenga T E (eds), 1999. Conservation tillage with animal traction. A resource book of the
Animal Traction Network for Eastern and Southern Africa (ATNESA). Harare. Zimbabwe. 173p. A publication supported by French Cooperation, Namibia. For details of ATNESA and its resource publications, see http://www.atnesa.org