Farmers' Knowledge and Sustainable Agroecosystem Management: An Operational Definition and an Example from Chiapas, Mexico Mauricio R. Bellon A1 A1 Associate Researcher Centro de Ecología, Universidad Nacional Autónoma, México Abstract: Indigenous knowledge of small farmers in the tropics may provide important contributions to the development of sustainable agricultural systems. This article examines this idea, particularly under conditions of socioeconomic and technological change. It develops an operational definition of sustainable agroecosystem management and links it to farmers' indigenous knowledge. It analyzes the management of soils and germplasm by a group of small maize farmers in Chiapas, Mexico. It shows that sustainable and nonsustainable managements can coexist in the same agroecosystem, and points out that an important part of the value of farmers' indigenous knowledge is to identify the incentives that lead to either management style. Inglés