Evidence of an emerging focus on the role of farmer knowledge in developed countries is highlighted by the debate on the nature of local and scientific knowledge. Less attention has been paid to the interaction of different ways of knowing for sustainable capital-intensive agriculture. This paper explores the relationship between local and scientific knowledge in managing temperate pasture and grazing systems in Australia. The nature of farmer knowledge is firstly examined by describing the experiences of farm families in managing native and introduced perennial grasses in upland areas of the Murray-Darling Basin. The building of knowledge and skills through social learning was explored in group case studies and interviews with stakeholders involved in pasture research and development. The interchange of local and scientific knowledge in groups was shown to have a synergistic effect, whereby local knowledge was broadened and strengthened, and scientific knowledge adapted and molded to specific situations. The effectiveness of social learning was greatest in collaborative programs based on small, local groups involved in monitoring and evaluation of whole farm pasture and grazing systems.