First Workshop ESSP Bioenergy

Bioenergy and Earth SustainabilityUniversity of São Paulo

Centro de Energia Nuclear na AgriculturaEscola 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)

GLOBAL VIEW - Ethanol

North

Northeast

Center-West

Southeast

South

Brazil

Nitrogen fertilizers in sugar cane

Sugar cane: 80 -100 kg N.haSugar cane: 80 -100 kg N.ha-1-1.yr.yr-1-1

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

Most as UREA – (CO(NH(CO(NH22))22))

Losses of UREA: volatilization and nitrification

Volatilization: 1.UREA is transformed in ammonium carbonate2. Ammonium carbonate under high pH and temperature is transformed in NHNH33

Nitrification:1. NH3 is oxidized into NH4

+

2. NH4 is nitrified to NO3-

3. NO3- is leached out of the soil profile or

4. NO3- is denitrified to NN22OO

NH4+ NO3

-

N2

OMMineralization nitrification

N2O + N2 denitrification

Biological fixation

NH3volatilization

UREA

N-harvestN-particle

Fonte: Trivelin, Gava, Oliveira (CENA); Vitti (ESALQ), Cantarella (IAC) -15N labeled fertilizer

Cana

Reciclagem

NH4+ NO3

-

N2

OMMineralization nitrification

N2O + N2 denitrification

Biological fixation

NH3volatilization

UREA

N-harvestN-particle

Fonte: Trivelin, Gava, Oliveira (CENA); Vitti (ESALQ), Cantarella (IAC)

Cana

Reciclagem

N wet deposition– kg N.ha-1.yr-1

Piracicaba * 5.0 – 6.0

NE - USA 6.0 – 8.0

Scandinavia 15.0

Central Amazonia * * 1.6

Balbina (Amazonia) *** 1.4

Rondônia (Amazonia) *** 0.8

NH4+ NO3

-

N2

OMMineralization nitrification

N2O + N2

denitrification

Biological fixation

NH3

volatilization

The Nitrogen Cycle – N-poor agricultural system

Reciclagem

N-harvest

Fonte: Cerri & Cerri (CENA), Melillo, Neill (WHOI), Bernoux (IRD)

Pastagem

N-fert

NH4+ NO3

-

N2

OMmineralization nitrification

N2O + N2

denitrification

biological fixation

NH3

volatilization

The Nitrogen Cycle – N-poor natural system

reciclagem

CerradoCerrado

deposition

Fonte: Bustamante, Miranda, Klink (UnB)

NH4+ NO3

-

N2

OMmineralization nitrification

N2O + N2

denitrification

biological fixation

NH3

volatilization

The Nitrogen Cycle – N-poor natural system

reciclagem

deposition

If Meq/M>1.0, there will be net climate warming, the greenhouse warming by in creased N2O release to the atmosphere then being larger than the quasi-cooling effect from “saved fossil CO2”.

NH4+ NO3

-

N2

OMMineralization nitrification

N2O + N2

Biological fixation

NH3volatilization

UREA

N-harvest

Reciclagem

N-particle

Fonte: Trivelin, Gava, Oliveira (CENA); Vitti (ESALQ), Cantarella (IAC), Urquiaga (Embrapa)

Cana

denitrification