A Phosphorus Flow Analysis of Brazil

摘要

Brazil is one of the major agricultural producers and phosphorus consumers of the world. Phosphorus (P) management in the country has direct impacts in the global cycle of this resource. In this context, this study proposes a Phosphorus Flow Analysis for Brazil, using the Mass Flow Analysis method to create a conceptual model of major P flows and stocks at the country scale, considering the base year of 2013. A total of 10 processes and 46 flows were identified and quantified. Results showed that, for the year of study, Brazil had a P input of 1.7 × 103 Gg P/year, mainly in the form of P-fertilizers, and a P output of 4.7 × 102 Gg P/year, mainly as grains exports. Agricultural soils were the main stock of P in the country. From the 2.6 × 103 Gg P/year applied in arable soils, 40% remain in the soil, with other 40% leaving as crop products, and 16% being lost through erosion and runoff to the hydrosphere. P flow in the food actually consumed by the population was 1.8 × 102 Gg P/year, only 8% of total P-fertilizer inputs in agricultural soils. About 6.5 × 102 Gg P/year was lost to the environment. There were no significant flows of P reuse and recycling during the study year. Scarcity scenarios and opportunities for sustainable use of P are discussed, along with the main environmental impacts caused by phosphorus production and consumption in Brazil.