Most small-holder farmers in southern Africa rely on maize as their staple food and manage mixed crop/livestock systems where maize is the major crop and maize residues provide a vital source of livestock feed during the dry season when grazing areas are limited. Conservation agriculture on the other hand relies on ground cover with crop residues to achieve its potential to increase crop yields under rainfed conditions and increase soil health and system sustainability. The competition between the soil and animals for the scarce crop residues thus has become a major point for discussion and often disagreement. However, most analyses of total farm productivity during a transition to conservation agriculture from tillage-based agriculture assume that all of the farm will be converted to the new system in a relatively short period of time. This strategy, while conceptually simple, also results in the maximum competition for residues, and as a result tends to force a decision against CA before its promise of increased yields and system sustainability can be achieved. If the farm is converted gradually to CA, then competition is less, the farmer can learn to manage the new system properly under his/her conditions, and soil degradation on the farm can gradually be reverted while crop productivity increases. The reduced risk of crop failure with CA also allows diversification of crops on the farm, and may include the production of forage crops with markedly better nutritional quality than cereal crop residues. Using examples from farmer managed plots in southern Africa the paper will explore the effects on total productivity. However, there are other difficulties with surface residue retention, principally communal grazing rights after harvest and the prevalence of wild fires or bush fires. Both of these need to be taken into account and while the farmer can control aspects of the solution, overcoming the problems will involve important policy decisions at the community and district levels.

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