Quantifying the contribution of crop-livestock integration to African farming.

Smallholder farming systems in Sub-Saharan Africa are often nutrient-limited systems that depend largely on the use of land resources for their subsistence. Crop-livestock integration is an effective means by which nutrients can be rapidly recycled within and between farms. However, there is great uncertainty over which are the critical stages of nutrient transfer through crop-livestock systems. Each transfer of nutrients within the farming system provides a risk of inefficiency, which depends on the type of system, its management practices and site conditions. Because livestock fulfil several functions in crop-livestock systems, and farmers manage their animals according to the weight assigned to each function, there are trade-offs between increasing animal productivity, and income from livestock and sustaining crop production through cycling nutrients from animal manure. This thesis is a contribution to development of an analytical tool, the NUANCES framework, to support the analysis of trade-offs in crop-livestock sys- tems, with focus on opportunities for intensification and maximisation of the benefits from crop-livestock integration for smallholder farmers...