Nitrogen mass balance in the Brazilian Amazon: an update

• Published in: Brazilian journal of biology Vol. 72; no. 3 Suppl; pp. 683 - 690
• Main Authors: Martinelli, L A, Pinto, A S, Nardoto, G B, Ometto, J P H B, Filoso, S, Coletta, L D, Ravagnani, E C
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil Instituto Internacional de Ecologia 01.08.2012
• Subjects: Agriculture; Amazon; Animals; biological nitrogen fixation; BIOLOGY; Brazil; Cattle; Environmental Monitoring - methods; Fertilizers; Humans; land use changes; Models, Biological; Nitrogen - metabolism; nitrogen balance; Population Growth; Sewage; Urbanization; Brazil; land use changes; Amazônia; fixação biológica do nitrogênio; mudança do uso da terra; nitrogen balance; urbanização; biological nitrogen fixation; Amazon; urbanization; balanço do nitrogênio
• ISSN: 1519-6984; 1678-4375; 1678-4375; 1519-6984
• DOI: 10.1590/S1519-69842012000400007

The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Amazon region. The main inputs of nitrogen to the region are biological nitrogen fixation occurring in tropical forests (7.7 Tg.yr(-1)), and biological nitrogen fixation in agricultural lands mainly due to the cultivation of a large area with soybean, which is an important nitrogen-fixing crop (1.68 Tg.yr(-1)). The input due to the use of N fertilizers (0.48 Tg.yr(-1)) is still incipient compared to the other two inputs mentioned above. The major output flux is the riverine flux, equal to 2.80 Tg.yr(-1) and export related to foodstuff, mainly the transport of soybean and beef to other parts of the country. The continuous population growth and high rate of urbanization may pose new threats to the nitrogen cycle of the region through the burning of fossil fuel and dumping of raw domestic sewage in rivers and streams of the region.