Brazilian Agriculture: The Transition to Sustainability

Brazil has a total area of 850 million ha, of which 90% is within the tropics. Historically, the system of exploitation of the land for agriculture and forestry was based on land clearing, cultivation for some years and then moving on to new areas. This process often left degraded areas behind, especially in the mountainous areas of the country. With modern agricultural technology, crops can be successfully grown in virtually any region of the country. The current challenge for Brazil is to feed its population and provide agricultural surpluses for the growing export markets, while preserving its rich and biologically-diverse native vegetation which still covers almost half of the country. The objective of this review is to trace the history of agricultural activity in this country, and to assess the sustainability of the cropping and pasture systems which today occupy the largest areas. At present approximately 50 million ha are under annual and perennial crops, while almost twice this area is under pastures. These pastures, predominately Brachiaria spp., are mostly in a degraded state due to lack of fertilization and over grazing. The various options available to recover these pastures or convert these areas for sustainable cropping are explained. In recent years, increasing proportions of soybean, wheat, and corn are produced under zero tillage which favors the conservation of soil organic matter. This not only radically reduces the risk of erosion but also increases the capacity of the soils to retain nutrients and water. Small holders who represent a considerable fraction of Brazil's food crop production, generally do not have access to fertilizers or other agricultural chemicals. They obtain very low yields and their farming practices exhaust the soil of nutrients. The Brazilian sugarcane industry is the largest in the world and recent changes in the management of this crop and its impact upon sustainability issues are also discussed. Brazil also has vast areas of degraded pastures and abandoned hillsides that can be used for agricultural expansion. This would prevent further destruction of native vegetation and its accompanying biological diversity for agriculture.