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
THINKINGbeyond the canopy
23 February 2012 – ICOPE, Bali

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)

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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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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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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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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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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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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“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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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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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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N2O emissions in the fertilised zone
700
N0
N2O (g N-N2O ha-1 d-1)
600 N1
500 N2
400
300
200
100
0
-100
-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Days after fertilization
 N2ON2> N2ON1> N2ON0 (P < 0.0001)
N dose Cumulated N2O emissions
 Cumulated emissions (kg N-N2O ha-1 28 days)
N0 0.3 ± 0.3
N1 2.4 ± 1.1
N2 8.8 ± 1.7
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N2O emissions at the plot scale and
emission factor (Ef)
 Cumulated emissions plot scale
N dose Cumulated N2O emissions
(kg N-N2O ha-1 28 days)
N0 0.3 ± 0.3
N1 0.5 ± 0.4
N2 1.0 ± 0.6
1.2
(kg N-N2O ha-1 28 days)
 Emission factor
Cumulative N2O plot
1.0
0.8
0.6
Ef = 2.5% ± 0.1% 0.4
y = 0.025x + 0.03
0.2 R² = 0.94
0.0
0 10 20 30
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N dose (kg N ha-1)canopy

CH4 emissions fertilised zone & plot scale
90
N0
CH4 (g C-CH4 ha-1 d-1)
70 N1
N2
50
30
10
-10
-30
-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Days after fertilization
 No significant between N doses treatments (P = 0.3)
 Cumulated emissions
N dose Cumulated CH4 emissions FZ Cumulated CH4 emissions Plot Scale
(kg C-CH4 ha-1 28 days) (kg C-CH4 ha-1 28 days)
N0 0.2 ± 0.2 0.2 ± 0.2
N1 0.6 ± 0.5 0.2 ± 0.2
N2 0.4 ± 0.4 0.2 ± 0.2 THINKING beyond the canopy

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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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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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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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

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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