Conservation Agriculture in Eastern and Southern Africa

Abstract

It is generally understood and well documented that conventional farming practices with frequent ploughing gradually degrade the physical structure of tropical soils (Brady and Weil, 2007) leading to increased soil erosion and decreased chemical quality of tropical soils. These processes are the same, but possibly somewhat slower, in subtropical areas. There have been numerous efforts, many ongoing, to develop functional Conservation Agriculture (CA) systems in eastern and southern Africa (E&S Africa) to overcome the negative effects of tillage-induced degradation, led by multiple institutions including public, commercial, religious, research and development organizations. In general, all efforts have endeavoured to implement systems based on the three principles of CA; minimal soil disturbance, soil cover with living plants or crop residues, and crop rotation (FAO). However, often only one or two of these principles have been applied and the techniques, focus and methodologies employed have been as diverse as the organizations supporting the efforts. Recently some papers have suggested that CA is only applicable to small pockets of farmers in E&S Africa, and that the systems are constrained by numerous challenges that are considered insurmountable (Giller et al., 2009; Andersson and Giller, 2012). Those developing CA systems in the quest for sustainable agricultural production for farmers in Africa, smallholders and commercial farmers alike, have often acknowledged these same problems (e.g. Wall, 2007), and have dedicated considerable efforts to overcoming them, considering, therefore, that the challenges are surmountable. Given the confusion that these two different positions have provoked among many of those labouring to advance African agriculture, this chapter examines research results from E&S Africa in an effort to develop a clearer picture of the future of CA systems in the region.