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 systems, with focus on opportunities for intensification and maximisation of the benefits from crop-livestock integration for smallholder farmers. The framework that was developed can be used to analyse options for intensification at different scales, from the cattle sub-system, farm scale to village scale.

List of content:

Chapter 1: General introduction

Chapter 2: Nitrogen cycling efficiencies through resource-poor African
crop-livestock systems

Chapter 3: Manure as a key resource within smallholder farming
systems: Analysing farm-scale nutrient cycling efficiencies
with the NUANCES framework

Chapter 4: Lifetime productivity of dairy cows in smallholder farming
systems of the highlands of East Africa

Chapter 5: Analysing integration and diversity in agro-ecosystems by
using indicators of network analysis

Chapter 6: Characterisation of N flows and cycling in smallholder croplivestock
systems of the highlands of East and southern Africa

through network analysis
Chapter 7: Collective management of feed resources at village scale and
the productivity of different farm types in a smallholder
community of North East Zimbabwe

Chapter 8: General discussion