Evaluation of nitrogen status of agricultural soils in Java, Indonesia

Figures & data

Figure 1 Location of the sampling sites in Java, Indonesia.

Table 1 Number of soil samples in relation to soil group and land use

Soil group	Paddy	Upland	Total
Andosols	2	8	10
Acrisols	3	5	8
Fluvisols	8	1	9
Luvisols	6	4	10
Nitisols	2	2	4
Vertisols	2	3	5
Total	23	23	46

Table 2 Descriptive statistics of the contents of Total-N, Iex-N, Ifix-N, Omin-N and Osta-N of the soils

	Total-N g kg^−1	Iex-N mg kg^−1	Ifix-N mg kg^−1	Omin-N mg kg^−1	Osta-N g kg^−1
Arithmetic mean	2.06	25.8	99.1	103	1.83
Geometric mean	1.81	22.0	–	81.1	1.57
Median	1.84	20.0	36.7	87.6	1.67
Maximum	6.79	83.1	580	368	6.68
Minimum	0.76	9.9	0.0	5.3	0.58
Coefficients of variation (%)	58.3	63.5	142	66.2	64.4
Ratio to total N (%)	100	1.3	4.8	5.0	88.9

Iex-N: inorganic extractable N, Ifix-N: fixed ammonium N, Omin-N: organic mineralizable N, Osta-N: organic stable N.

Table 3 Descriptive statistics of selected physicochemical properties of the soils

	Total-C g kg^−1	Alo + 1/2Feo g kg^−1	Nonex-K mg kg^−1	Sand g kg^−1	Silt g kg^−1	Clay g kg^−1	pH
Arithmetic mean	21.6	25.2	338	180	327	493	6.64
Median	17.8	11.4	257	87	325	512	6.69
Maximum	79.4	258.2	1368	704	548	807	8.55
Minimum	7.6	1.4	70.4	16	139	68	4.99
CV (%)	68.5	194	76.9	112	33.7	42.9	15.1

Nonex-K: nonexchangeable K.

Figure 2 Relationship between non-exchangeable potassium (K) and fixed ammonium-nitrogen (Ifix-N).

Table 4 Correlation coefficients between nitrogen (N) fractions and selected physicochemical properties of the soils

	Total-N	Iex-N	Ifix-N	Omin-N	Osta-N
Total-C	0.96**	0.33*	−0.12	0.21	0.95**
Alo + 1/2Feo	0.82**	0.20	−0.20	0.11	0.83**
Non-exchangable K	−0.08	−0.06	0.92**	−0.07	−0.18
sand	−0.13	−0.02	−0.34**	−0.16	−0.09
silt	0.41**	0.03	0.05	−0.17	0.41**
clay	−0.09	0.01	0.29*	0.24	−0.13
pH	−0.57**	−0.40**	0.19	−0.16	−0.58**

** and * indicate statistical significance at the level of p < 0.01 and p < 0.05, respectively.

Iex-N: inorganic extractable N, Ifix-N: fixed ammonium N, Omin-N: organic mineralizable N, Osta-N: organic stable N.

Table 5 Arithmetic mean of the contents and percentages of the soil nitrogen (N) fractions in relation to soil type

		Total-N	Iex-N		Ifix-N		Omin-N		Osta-N
Soil type	No.	g kg^−1	mg kg^−1	%	mg kg^−1	%	mg kg^−1	%	g kg^−1	%
Andosols	10	3.38a	27.9ab	0.8a	43.4b	1.3b	128a	3.8a	3.18a	94.1a
Acrisols	8	2.26ab	42.9a	1.9a	37.2b	1.7b	109a	4.8a	2.07ab	91.6a
Fluvisols	9	1.78b	21.2b	1.2a	295a	17a	103a	5.8a	1.36b	76.5b
Luvisols	10	1.42b	20.0b	1.4a	51.2b	3.6b	81.0a	5.7a	1.27b	89.3a
Nitisols	4	1.55b	19.9b	1.3a	80.7b	5.2b	56.3a	3.6a	1.40b	89.9a
Vertisols	5	1.30b	18.9b	1.5a	68.0b	5.3b	125a	9.6a	1.08b	83.7ab
Average	46	2.06	25.8	1.3	99.1	4.8	103	5.0	1.83	88.9

Means followed by the same letter are not significantly different at the p < 0.05 level.

Iex-N: inorganic extractable N, Ifix-N: fixed ammonium N, Omin-N: organic mineralizable N, Osta-N: organic stable N.

Table 6 Arithmetic mean of the contents and percentages of the soil nitrogen (N) fractions in relation to land use

		Total-N	Iex-N		Ifix-N		Omin-N		Osta-N
Land use	No.	g kg^−1	mg kg^−1	%	mg kg^−1	%	mg kg^−1	%	g kg^−1	%
Paddy	23	1.83	20.8	1.1	172	9.4	95.9	5.2	1.55	84.3
Upland	23	2.29	30.8	1.3	26.3	1.2	110	4.8	2.12	92.7
Significance		ns	*	*	**	**	ns	ns	ns	**

**, *, and ns indicate statistically significant at the level of p < 0.01 and p < 0.05 and not significant, respectively.

Iex-N: inorganic extractable N, Ifix-N: fixed ammonium N, Omin-N: organic mineralizable N, Osta-N: organic stable N.

Table 7 Arithmetic mean of the contents and percentages of the soil nitrogen (N) fractions in relation to elevation

		Total-N	Iex-N		Ifix-N		Omin-N		Osta-N
Elevation(m)	No.	g kg^−1	mg kg^−1	%	mg kg^−1	%	mg kg^−1	%	g kg^−1	%
1000∼	3	5.46a	40.4a	0.8a	17.8b	0.3b	117a	2.3a	5.29a	96.6a
500∼1000	5	2.71b	25.7a	1.1a	19.5b	0.8b	110a	4.3a	2.55b	93.9a
200∼500	6	1.17c	16.7a	1.5a	22.9b	2.0b	126a	10.5a	1.00c	86.0a
100∼200	9	2.16bc	35.4a	1.7a	24.7b	1.7b	120a	6.1a	1.98bc	90.6a
50∼100	5	1.42bc	31.3a	2.0a	54.4ab	4.5ab	94.3a	6.6a	1.24c	86.9a
0∼50	18	1.74bc	20.1a	1.2a	210a	11.9a	85.3a	4.7a	1.42c	82.2a
Average	46	2.06	25.8	1.3	99.1	4.8	103	5.0	1.83	88.9

Means followed by the same letter are not significantly different at the p < 0.05 level.

Iex-N: inorganic extractable N, Ifix-N: fixed ammonium N, Omin-N: organic mineralizable N, Osta-N: organic stable N.

Table 8 Comparison of the contents of soil nitrogen (N) fractions between Java and Japan

		Total-N	Iex-N	Ifix-N	Omin-N	Osta-N
	No.	g kg^−1	mg kg^−1	mg kg^−1	mg kg^−1	g kg^−1
Japan^1	147	2.59	37.2	124	159	2.27
Java	46	2.06	25.8	99	103	1.83
Significance		*	**	ns	**	*
Java/Japan (%)		80	69	90	65	80

¹Sano et al. (2004).

Iex-N: inorganic extractable N, Ifix-N: fixed ammonium N, Omin-N: organic mineralizable N, Osta-N: organic stable N.

Sano S, Yanai J, Kosaki T 2004:   Evaluation of soil nitrogen status in Japanese agricultural lands with reference to land use and soil types. Soil Sci. Plant Nutr., 50, 501–510. doi:10.1080/00380768.2004.10408506

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