| Summary: | No-till or direct seeding is a production system based on non-ploughing. It incorporates a range of farming practices that protect agricultural soils from erosion, reduce fuel consumption and could increase crop yields. The broad success of no-till in Brazil, contributes to the competitiveness and growth of its products while conserving soils. The complete system of conservation agriculture is based on three principles: no tillage, permanent soil cover and crop rotations. In the field, the practices are varied and many farmers apply so the first principle. The system, however, is most often associated with the use of herbicides that induce risks of pollution, yet little studied in Brazil. No-till has become established in southern Brazil in the years 1970-1990. Hence, the system implemented by the gaúchos, quickly spread to other regions, particularly in central and northern Brazil. In this paper, the practices of no-till are studied at two scales. The region of Paraná 3, located in eastern edge of Lake Itaipu dam, shows that the practice of no-till, adopted by many farmers also includes the protection of the dam to control erosion and water pollution. At farm level, interviews with three farmers of Paraná and Rio Grande do Sul, realizing the no-till with cover crops, present the practices and the knowledge associated with them. These interviews show that the adoption of a conservation farming system is based on a deep change of the production system and appropriation of knowledge about natural processes. The success of no-till is based on increasing incomes but the sustainability of soil use requires a integrated approach associating no-till with cover crops and crop rotation.
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