A View of Soil Management and Climate Change Challenges in Southern Africa.

Southern Africa is largely characterized by a unimodal rainy season from October to March, followed by a long dry spell in winter conforming with an arid to semi-arid environment, locally tempered by altitude.  Regions bordering the Indian ocean receive higher annual rainfall than those on the Atlantic seaboard.  The annual rainfall is erratic and highly variable, especially early in the wet season when intense storms of short duration occur.  Despite some disagreement between climate change models in the magnitude of rainfall change, there is similarity in the direction and spatial distribution of change:  drier to the west and wetter to the east with uncertainty in the interior.  The temperature is expected to increase across the region, by as much as 3 to 4°C in the interior.

Farming in southern Africa varies from extensive livestock production on rangeland to intensive crop production under irrigation, practised by subsistence to commercial farmers on a diversity of natural agricultural resources.  The strong seasonality of rainfall in combination with very high evapotranspiration makes stock and crop farming vulnerable to droughts that are common.  Droughts are aggravated by inappropriate management practices that exhaust for example soils of nutrients and organic matter.  The latter serves as either a source or sink for atmospheric carbon dioxide that is one of the greenhouse gases contributing to climate change.  Impacts of different kinds of land use and coinciding management practices on soil organic matter contents will be addressed through several case studies from the region.  Based on knowledge from these case studies the challenges facing soil management in mitigating the effects of expected climate change will be discussed.