Effect of soil types and nitrogen fertilizer on nitrous oxide and carbon dioxide emissions in oil palm plantations

Figures & data

Figure 1 Map of study sites in Indonesia and Malaysia.

Figure 2a Precipitation, soil moisture tension, soil temperature, nitrous oxide (N₂O) flux and carbon dioxide (CO₂) flux in Tunggal sandy loam soil. Vertical bars indicate ± standard deviation. Treatment B: no nitrogen (N) fertilizer and no tillage; C: conventional fertilizer; B2: no N fertilizer with tillage; M: coated fertilizer. Solid arrows and dashed arrows indicate conventional and coated fertilization timing, respectively. Vertical dashed lines indicate transition period for dry and wet seasons.

Figure 2b Precipitation, soil moisture tension, soil temperature, N₂O flux, and CO₂ flux, in Simunjan sandy soil. See details for other remarks in Fig. 2a.

Figure 2c Precipitation, soil moisture tension, soil temperature, N₂O flux, and CO₂ flux, in Tatau peat soil. See details for other remarks in Fig. 2a.

Table 1 Descriptions and physicochemical characteristics of soils at the oil palm plantation study sites

	Study sites
Description	Tunggal	Simunjan	Tatau
Soil type	Sandy loam (62% sand, 5% clay, 33% silt)	Sandy (97% sand, 0.03% clay, 2.97% silt)	Peat
Total area (ha)	14,000	7900	9000
Studied area (ha)	93.6	4.4	3.52
Planting density (palm ha^−1)	135	136	150
Age of palm trees	7 yr. (mature)	9 yr. (mature)	4 yr. (immature)
Pre-oil palm vegetation	Rubber plantation	Primary and secondary forest	Acacia garden
NO3^– (mg N kg^−1 ds)	16.2 ± 7.61	1.41 ± 0.93	77.8 ± 18.6
NH4^+ (mg N kg^−1 ds)	31.9 ± 8.05	16.2 ± 12.1	122.8 ± 22.1
Total N (gkg^−1 ds)	2.17 ± 0.31	1.70 ± 0.26	17.2 ± 3.90
Total C (g kg^−1 ds)	23.4 ± 4.71	18.5 ± 0.56	467 ± 71.0
pH (KCl)	4.67 ± 0.10	4.77 ± 0.06	3.34 ± 0.08
Bulk density (g cm^−3)	1.1 ± 0.1	1.5 ± 0.0	0.2 ± 0.0
WFPS (%)	75.9 ± 3.0	74.4 ± 1.2	83.5 ± 4.0

yr., year, means ± standard deviation, n = 3. nitrate (NO₃^–); ammonium (NH₄⁺); total nitrogen (Total N); total carbon (Total C); bulk density (BD); water-filled pore space (WFPS). Rubber (Hevea brasiliensis); Acacia (Acacia mangium). Soil sampling was conducted in August 2011, before fertilizer application on fine days with no rain during the dry season.

Table 2 Nitrous oxide (N₂O) fluxes for the three study sites during wet and dry seasons

Study sites	Treatments	N2O flux (μg N m^−2 h^−1)
		Wet season	Dry season
Tunggal	B	33.7 ± 49.6	6.27 ± 0.44
	B2	27.4 ± 20.3	19.1 ± 4.52
	C	89.7 ± 14.1	17.3 ± 1.45
	M	28.2 ± 36.0	8.30 ± 5.87
Simunjan	B	3.81 ± 1.42	2.40 ± 4.79
	B2	0.80 ± 3.65	1.63 ± 1.12
	C	1.60 ± 1.57	3.20 ± 2.51
	M	2.18 ± 2.73	5.34 ± 7.03
Tatau	B	131 ± 77.2	66.1 ± 49.9
	B2	523 ± 441	93.7 ± 80.6
	C	249 ± 77.3	185 ± 15.5
	M	272 ± 151	606 ± 421
ANOVA	df	F value	p value
Sites	2	28.925	0.000
Treatments	3	2.282	0.091
Seasons	1	0.876	0.354
Sites × treatments	6	2.449	0.038
Sites × seasons	2	0.303	0.740
Treatments × seasons	3	2.755	0.053
Sites × treatments × seasons	6	2.811	0.020

Data are presented as the means ± standard deviation (n = 3). B, no fertilizer with no tillage; B2, no fertilizer with tillage; C, conventional fertilizer; M, coated fertilizer; N, nitrogen; ANOVA, analysis of variance; df, degrees of freedom. Wet season: from October to March; dry season: from April to September.

Table 3 Cumulative nitrous oxide (N₂O) fluxes for the three study sites

Study sites	Cumulative N2O fluxes (kg N ha^−1 period^−1)
	B	B2	C	M
Tunggal	0.59 ± 0.11	2.14 ± 0.64	4.09 ± 0.84	1.99 ± 2.16
Simunjan	0.25 ± 0.14	0.11 ± 0.08	0.18 ± 0.18	0.42 ± 0.30
Tatau	11.1 ± 7.02	22.5 ± 18.9	24.2 ± 6.58	42.7 ± 24.6
ANOVA	df	F value	p value
Sites	2	25.937	0.000
Treatments	3	2.115	0.125
Sites × treatments	6	1.881	0.126

Data are presented as the means ± standard deviation (n = 3). B, no fertilizer with no tillage; B2, no fertilizer with tillage; C, conventional fertilizer; M, coated fertilizer; N, nitrogen; ANOVA, analysis of variance; df, degrees of freedom.

Table 4 Emission factors (EF) calculated for the three study sites

Study sites	EF (%)
	C	M
Tunggal	2.29 ± 0.33	−0.33 ± 0.35
Simunjan	−0.26 ± 0.08	0.49 ± 0.40
Tatau	19.13 ± 2.46	43.8 ± 16.7
ANOVA	df	F value	p value
Sites	2	40.012	0.000
Treatments	1	5.415	0.038
Sites × treatments	2	6.931	0.010

Data are presented as the means ± standard deviation (n = 3). C, conventional fertilizer; M, coated fertilizer; ANOVA, analysis of variance; df, degrees of freedom.

Table 5 Pearson correlation of nitrous oxide (N₂O) emission factors (EF) between the conventional fertilizer and the coated fertilizer among soil parameters for the three study sites (n = 9)

Soil Parameters	N2O EF (%)
	C	M
NO3^–	0.966**	0.794*
NH4^+	0.960**	0.832**
Total N	0.951**	0.850**
Total C	0.954**	0.939**
pH	−0.979**	−0.943**
BD	−0.977**	−0.891**
WFPS	0.834**	0.729*

EF, emission factors; C, conventional fertilizer; M, coated fertilizer;

** significant at 0.001; * significant at 0.05. nitrate (NO₃^–); ammonium (NH₄⁺); total nitrogen (Total N); total carbon (Total C); bulk density (BD); water-filled pore space (WFPS).

Table 6 Carbon dioxide (CO₂) fluxes for the three study sites during the wet and dry seasons

Study sites	Treatments	CO2 flux (mg carbon m^−2 h^−1)
		Wet season	Dry season
Tunggal	B	45.5 ± 0.93	56.4 ± 2.78
	B2	50.6 ± 11.3	61.3 ± 6.05
	C	49.0 ± 18.9	95.4 ± 10.9
	M	56.8 ± 15.3	96.5 ± 15.1
Simunjan	B	72.1 ± 10.9	104 ± 8.55
	B2	71.1 ± 3.66	134 ± 34.5
	C	101 ± 14.0	126 ± 10.2
	M	114 ± 7.93	105 ± 46.5
Tatau	B	89.8 ± 43.5	92.7 ± 23.1
	B2	223 ± 93.2	129 ± 31.7
	C	158 ± 45.0	153 ± 75.7
	M	153 ± 49.9	208 ± 107
ANOVA	df	F value	p value
Sites	2	34.525	0.000
Treatments	3	4.287	0.059
Seasons	1	1.576	0.215
Sites × treatments	6	1.608	0.165
Sites × seasons	2	2.179	0.124
Treatments × seasons	3	1.051	0.379
Sites × treatments × seasons	6	1.450	0.216

Data are presented as the means ± standard deviation (n = 3). B, no fertilizer with no tillage; B2, no fertilizer with tillage; C, conventional fertilizer; M, coated fertilizer; ANOVA, analysis of variance; df, degrees of freedom. Wet season: from October to March; dry season: from April to September.

Table 7 Cumulative carbon dioxide (CO₂) fluxes for the three study sites

Study sites	Cumulative CO2 fluxes (kg carbon ha^−1 period^−1)
	B	B2	C	M
Tunggal	5302 ± 420	5655 ± 634	6888 ± 112	7971 ± 172
Simunjan	9002 ± 467	7638 ± 139	10803 ± 165	11431 ± 371
Tatau	8797 ± 364	13588 ± 407	15328 ± 608	16950 ± 690
ANOVA	df	F value	p value
Sites	2	13.62	0.000
Treatments	3	3.094	0.064
Sites × treatments	6	0.657	0.684

Data are presented as the means ± standard deviation (n = 3). B, no fertilizer with no tillage; B2, no fertilizer with tillage; C, conventional fertilizer; M, coated fertilizer; ANOVA, analysis of variance; df, degrees of freedom.