1. First Workshop ESSP Bioenergy Bioenergy and Earth Sustainability University of São Paulo Centro de Energia Nuclear na Agricultura Escola Superior de Agricultura “Luiz de Queiroz” 19-21 July 2008 “Nitrogen dynamics and sugar cane in Brazil” Luiz A Martinelli (CENA/USP) Reynaldo L Victoria (CENA/USP) Janaina Braga do Carmo (UFSCar-Sorocaba) Jean Pierre Ometto (IGBP-INPE)

2. GLOBAL VIEW - Ethanol

3. North Northeast Center-West Southeast South Brazil

4. Nitrogen fertilizers in sugar cane Sugar cane: 80 -100 kg N.ha -1.yr -1 Pasture: 0 kg N.ha -1.yr -1 Soybean: 0 kg N.ha -1.yr -1 (BNF) Corn: 150-200 kg N.ha -1.yr -1 Coffee: 250-300 kg N.ha -1.yr -1 (CO(NH 2 ) 2 ) Most as UREA – (CO(NH 2 ) 2 ) Losses of UREA: volatilization and nitrification Volatilization: 1.UREA is transformed in ammonium carbonate NH 3 2. Ammonium carbonate under high pH and temperature is transformed in NH 3 Nitrification: 1. NH 3 is oxidized into NH 4 + 2. NH 4 is nitrified to NO 3 - 3. NO 3 - is leached out of the soil profile or N 2 O 4. NO 3 - is denitrified to N 2 O Nitrogen fertilizers in sugar cane Sugar cane: 80 -100 kg N.ha -1.yr -1 Pasture: 0 kg N.ha -1.yr -1 Soybean: 0 kg N.ha -1.yr -1 (BNF) Corn: 150-200 kg N.ha -1.yr -1 Coffee: 250-300 kg N.ha -1.yr -1 (CO(NH 2 ) 2 ) Most as UREA – (CO(NH 2 ) 2 ) Losses of UREA: volatilization and nitrification Volatilization: 1.UREA is transformed in ammonium carbonate NH 3 2. Ammonium carbonate under high pH and temperature is transformed in NH 3 Nitrification: 1. NH 3 is oxidized into NH 4 + 2. NH 4 is nitrified to NO 3 - 3. NO 3 - is leached out of the soil profile or N 2 O 4. NO 3 - is denitrified to N 2 O

6. NH 4 + NO 3 - N2N2 OM Mineralization nitrification N 2 O + N 2 denitrification Biological fixation NH 3 volatilization UREA N-harvest N-particle Fonte: Trivelin, Gava, Oliveira (CENA); Vitti (ESALQ), Cantarella (IAC) - 15 N labeled fertilizer Cana Reciclagem

7. NH 4 + NO 3 - N2N2 OM Mineralization nitrification N 2 O + N 2 denitrification Biological fixation NH 3 volatilization UREA N-harvest N-particle Fonte: Trivelin, Gava, Oliveira (CENA); Vitti (ESALQ), Cantarella (IAC) Cana Reciclagem

8. N wet deposition– kg N.ha -1.yr -1 Piracicaba * 5.0 – 6.0 NE - USA6.0 – 8.0 Scandinavia15.0 Central Amazonia * * 1.6 Balbina (Amazonia) *** 1.4 Rondônia (Amazonia) *** 0.8

9. 4.74.4 4.8 pH= 4.9

10. NH 4 + NO 3 - N2N2 OM Mineralization nitrification N 2 O + N 2 denitrification Biological fixation NH 3 volatilization The Nitrogen Cycle – N-poor agricultural system Reciclagem N-harvest Fonte: Cerri & Cerri (CENA), Melillo, Neill (WHOI), Bernoux (IRD) Pastagem N-fert

11. NH 4 + NO 3 - N2N2 OM mineralization nitrification N 2 O + N 2 denitrification biological fixation NH 3 volatilization The Nitrogen Cycle – N-poor natural system reciclagem Cerrado deposition Fonte: Bustamante, Miranda, Klink (UnB)

12. NH 4 + NO 3 - N2N2 OM mineralization nitrification N 2 O + N 2 denitrification biological fixation NH 3 volatilization The Nitrogen Cycle – N-poor natural system reciclagem deposition

13. If Meq/M>1.0, there will be net climate warming, the greenhouse warming by in creased N 2 O release to the atmosphere then being larger than the quasi-cooling effect from “saved fossil CO 2 ”.

14. NH 4 + NO 3 - N2N2 OM Mineralization nitrification N 2 O + N 2 Biological fixation NH 3 volatilization UREA N-harvest Reciclagem N-particle Fonte: Trivelin, Gava, Oliveira (CENA); Vitti (ESALQ), Cantarella (IAC), Urquiaga (Embrapa) Cana denitrification