B 3.4. What is the relative use of fertilizers for sugar-cane in Brazil and what is the environmental impact of it?
The use of fertilizers in Brazilian agriculture is, for the most part, relative low, although it has increased over the past thirty years, significantly reducing the need for new areas. Of the major crops in Brazil (taking up areas larger than 1 million ha), sugar-cane crops use less fertilizers than cotton, coffee and orange and an amount equivalent to that of soybeans. The use of fertilizers is also low compared to that of sugar-cane crops in other countries (~50 percent more fertilizers in Australia). The most important factor for that is the recycling of nutrients through the application of industrial waste (vinasse and filtercake), considering the limiting topography, soil and environmental control conditions. Substantial increases are observed in the Potassium content of the soils and in productivity as well. Recycling of nutrients is being optimized and straw recycling will be very important in expanding areas. A large number of studies related to leaching and the possibilities