Although nitrous oxide only makes up 8% of global greenhouse gas emissions, it has nearly 300 times the global warming potential of carbon dioxide. In this presentation, CIFOR scientist Kristell Hergoualc’h explains results from collaborative research between CIFOR, ICRAF, CIRAD and PT Bakrie, which show that nitrogen fertiliser can exacerbate the production of soil nitrous oxide greenhouse gases when applied to oil palms grown on deep peat. She gave this presentation on 23 February 2012 at the International Conference on Oil Palm & Environment (ICOPE) held in Bali, Indonesia. The conference had the theme ‘Conserving forest, expanding sustainable palm oil production’.
Carbon dioxide, methane and nitrous oxide emissions from an oil palm plantation on deep peat as affected by nitrogen fertilisation
1. CO2, CH4 and N2O emissions from an oil palm
plantation on deep peat as affected by N fertilisation
Kristell Hergoualc’h
Handayani E, Indrasuara, Samosir Y, van Noordwijk M, Bonneau X, Verchot L
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23 February 2012 – ICOPE, Bali
2. Climate change and greenhouse
gases
Increase in temperatures
Catastrophic
+ consequences
1°C
Anthropogenic cause: GHG emissions
F-gaz
GHG GWP
Share GHG N2O
8%
1%
CH4 CO2 1
14%
CO2 CH4 25
77%
NO2 298
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IPCC (2007)
3. Greenhouse gases and agriculture
IPCC (2007)
Global share GHG Agriculture
Atmospheric N2O (ppb)
N fertilizer consumption
46% N2O: Nitrogen fertilisation
(million tons N)
45% CH4 (livestock, rice fields)
9% CO2 (biomass combustion)
Baumert et al. (2005)
www.ferilizer.org/ifa/statistics
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4. Oil palm
World’s most rapidly
expanding crop
(Indonesia, Malaysia)
Expansion to the detriment of natural forests
Large C losses(Murdiyarso et al. 2010; Hergoualc’h & Verchot 2011)
Biodiversity losses (Danielsen et al. 2008)
Biofuel C debt (Fargione et al. 2008)
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5. Oil palm
Both on mineral (89%)
& peat soils (11%)
(Koh et al. 2011)
Voluntary RSPO and Government mandatory rules
forbid forest conversion and use of deep peat
Large doses of N fertiliser application:
Mineral soils: 50 – 230 kg N ha-1 y-1
Peat soils :50 – 160 kg N ha-1 y-1
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6. Research questions and hypothesis
How does N fertilisation affect GHG emissions in an oil
palm plantation on deep peat?
Short term and moderated in CH4& CO2 emissions
Long term and large in N2O emissions
How does the emission factor related to N2O emissions
arising from N fertilisation in an oil palm plantation on
peat compare with IPCC estimates?
Emission factor > IPCC estimates (recently opened peat with low N availability)
Can optimisation of N fertilisation GHG emissions per
unit product?
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7. Location and soil characteristics
Climate
2466 mm y-1, 26.5°C
Driest months: June – Sept.
Peat properties
Fibric
Depth (8.5 m)
pH (3.6)
Corg (42%)
Norg(1.2%)
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8. Experimental plot
Deforested in 04,
acquired by PT. Bakrie
in 07 in a state of fallow
Planted Dec. 09;
measurements Sep. 10
148 palms ha-1
Water table -56 cm
Fertiliser trial
Factorial design: 3 N x 3 P x 3 K, 2 Ca (54 plots, 8 rows x 4 palms)
N0: 0 kg N ha-1
N1:14 kg N ha-1 (20 kg N ha-1 2010, 48 kg N ha-1 2011)
N2: 28 kg N ha-1(40 kg N ha-1 2010, 96 kg N ha-1 2011) the canopy
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9. “In situ” measurements
Soil and air temperatures, soil moisture, water table depth
Soil effluxes of N2O, CO2, CH4 (closed chamber method)
Sampling frequency
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10. Methods
4 replicate chambers per N dose
Soil CO2 efflux: “in situ” IRGA
Soil N2O, CH4
4 samples/chamber Transportation to the Analysis by gas
(t0’, t10’, t20’, t30’) laboratory chromatography
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11. Extrapolation at the plot scale and
emission factor
FZ Zone Share plot N2O assigned
NFZ 92% N0
FZ 8% N1 / N2
NFZ
Example
N2O N1 Plot = 8% N2O N1 + 92% N2O N0
Emission factor Ef
Slope regression between N dose and GHG emissions
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15. CO2 emissions fertilised zone & plot scale
450
N0
CO2 (kg C-CO2 ha-1 d-1)
N1
350
N2
250
150
50
-50 -1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Days after fertilization
CO2 N2> CO2 N1 , CO2 N0 (P = 0.0002)
Cumulated emissions
N dose Cumulated CO2 emissions FZ Cumulated CO2 emissions Plot scale
(Mg C-CO2 ha-1 28 days) (Mg C-CO2 ha-1 28 days)
N0 1.9 ± 0.5 1.9 ± 0.5
N1 2.1 ± 0.2 1.9 ± 0.5
N2 2.7 ± 0.3 1.9 ± 0.5
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16. Oil palms response to fertiliser application
400
N0
Collar girth (cm)
N0
Palm Height (cm)
140
N1 N1
N2 300
100 N2
60 200
20 100
0 6 12 18 24 0 6 12 18 24
280 Months After Planting Months After Planting
Frond length (cm)
N0 35
Green leaf number
N0
240 N1 N1
N2 25 N2
200
160 15
120 5
6 12 18 24 6 12 18 24
0.8 Months After Planting Months After Planting
Hanging female bunches palm-1 24 MAP
N0
Vigor index
0.6 10
N1
8
0.4 N2
6
0.2 4
0.0 2
12 18 24 0
Months After Planting N0 N1 N2
No between N1 & N2 treatments
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17. Discussion
No correlation with soil and air temperatures, soil
moisture, water table depth: Short period observation
Comparison with literature
No study on the effect of N fertilisation on GHG emissions
from oil palm plantation
Melling et al. (06, 05): No intensive sampling after
fertilisation, largest N2O fluxes during wet season
N2 O CH4 CO2
(g N-N2O ha-1 d-1) (g C-CH4 ha-1 d-1) (kg C-CO2 ha-1 d-1)
This study (N0) 12.2 ± 4.7 6.0 ± 2.7 71.0 ± 10.6
Melling et al. 14 1.2 53
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18. Discussion
Very strong effect of N fertilisation on N2O emissions:
Ef = 2.5%
Peat recently opened and drained? Young age of the palms?
IPPC guidelines for GHG inventories (2006)*
Ef = 1% [0.3% – 3%]
Ef calculated as yearly N2O / N fertilisation rate
Effect N fertilisation on palm growth
+ effect N1 dose but no N1 & N2 doses also
observedon coconut palms(Bonneau et al., 93)
*Agriculture, Forestry & Other Land Use, Vol. 4, Chap. 11 (N2O emissions from managed soils, and CO2
emissions from lime and urea application) THINKING beyond the canopy
19. Conclusions
Complementary studies on GHG for improving Ef
- Experimental design improved with measurements in both
fertilised and non-fertilised zones (results under analysis)
- Yearly measurements including & fertilisation period in a 7-
year old plantation
GHG emission vs. Crop response to fertiliser
N2ON2 = 2 N2ON1
CropN2 CropN1 Reduction of emissions per unit
product feasible
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20. Thank you
www.cifor.cgiar.org
CIFOR advances human well-being, environmental conservation, and equity by conducting
research to inform policies and practices that affect forests in developing countries.
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