Are crop-livestock systems good models for the development of agroecological thinking?

The feasibility of achieving greater sustainability of animal production is highly debated. Some argue that pollution emissions from livestock farming (e.g., GHG, excess nitrogen, and loss of biodiversity), and increased allocation of land to monoculture for specialized and industrialized animal production systems, are significant to the debate over the environmental and social impacts of animal production. Others attest that the integration of agriculture and animal raising, in the form of mixed crop-livestock systems (CLSs), is important for the design of ecologically-based farming systems (Gliessman, 2006). Here, relying on case studies from Brazil and France, we examine if CLSs models contribute to agro-ecological thinking. First, we briefly describe the ecological principles likely to guide the design of more sustainable CLSs. We then show how the characteristics of mixed systems can have important contributions to a number of key ecological processes. Finally, we identify the main drivers that either favor or work against the development of such systems.