Regional trends in the chemical and mineralogical properties of upland soils in humid Asia: With special reference to the WRB classification scheme

Figures & data

Figure 1  Study area with soil moisture regimes.

Table 1 Outline of the sample soils

Sample group	No. samples^†	Sampling regions	Parent materials	Annual precipitation (soil moisture regimes)^‡	Mean annual temperature (soil temperature regimes)^‡
IDL	39 (10)	Low elevation area (< 600 m) of East Kalimantan, Java, and Sumatra islands of Indonesia	Sedimentary rocks (excluding limestone) and granite	> 1,500 mm (mostly udic)	> 22°C (hyperthermic)
IDH	10 (7)	High elevation area (> 600 m) of Kalimantan island of Indonesia	Sedimentary rocks (excluding limestone)	> 2,000 mm (perudic)	> 22°C (hyperthermic)
THL	40 (38)	Mainly low mountains (< 800 m) in northern Thailand	Sedimentary rocks (excluding limestone) and granite	1,200–1,600 mm, with distinct dry season (ustic)	> 22°C (hyperthermic)
THH	24 (22)	Mainly high mountains (> 800 m) in northern Thailand	Sedimentary rocks (excluding limestone) and granite		15–22°C (thermic)
JPS	30 (9)	South-temperate to sub-tropical zones of Japan	Sedimentary rocks (excluding limestone) and granite	Mostly > 1,500 mm, no dry season (udic or perudic)	> 15°C (thermic or hyperthermic)
JPN	20 (11)	North-temperate zone of Japan			8–15°C (mesic)
mafic	23 (7)	Mostly from Java and Smatra islands of Indonesia (partly from Thailand and Japan)	Volcanic rocks (intermediate to mafic) and limestone	> 1,500 mm (varying in soil moisture regimes: ustic, udic, and perudic)	> 15°C (thermic or hyperthermic)
Total	186 (104)
^†Clay mineralogy was reported in Watanabe et al. (2006) for soil samples numbered in parentheses.
^‡According to US Soil Taxonimy (Soil Survey Staff 2006).

Table 2 Average values of selected chemical and mineralogical properties of the soils from different regions

Sample group	No. samples	pH(H2O)		Clay		Total C^†		CECmin/clay		Fed^†		Clay mineral composition
												1.4 nm		1.0 nm		0.7 nm
		AVE	SE	AVE	SE	AVE	SE	AVE	SE	AVE	SE	AVE	SE	AVE	SE	AVE	SE
				(%)		(g kg^−1)		(cmolc kg^−1)		(g kg^−1)		(%)		(%)		(%)
Sorted by regions and parent materials
IDL	39	4.58	0.07 a	38.6	2.1 ab	5.4	0.5 a	32.4	1.5 bc	20.7	1.5 a	37	3 b	7	1 ab	56	3 cd
IDH	10	4.52	0.06 a	34.0	2.3 ab	6.5	1.0 ab	45.2	2.9 d	22.1	3.1 abc	37	5 b	18	4 abc	45	4 bc
THL	40	5.44	0.07 c	53.0	2.3 c	9.6	0.5 bc	22.2	1.3 a	37.3	2.6 cd	4	1 a	31	3 c	66	3 de
THH	24	5.50	0.09 c	47.2	3.2 bc	14.6	2.0 c	25.7	1.4 ab	40.8	5.0 bcd	12	2 a	17	4 b	71	4 ef
JPS	30	4.71	0.04 ab	35.1	2.4 a	12.9	2.6 bc	40.0	2.1 d	23.6	2.6 ab	58	4 c	11	2 ab	31	3 b
JPN	20	4.59	0.05 a	47.1	1.9 bc	33.4	3.0 d	39.9	2.2 cd	34.0	1.9 bcd	80	3 d	9	2 ab	11	2 a
Mafic	23	5.02	0.16 b	66.5	2.3 d	11.2	0.9 bc	31.4	2.9 bc	65.4	6.7 d	14	5 a	4	3 a	81	5 f
Sorted by reference soil groups
Andosols	4	4.66	0.06 ab	50.9	1.7 ab	46.0	5.8 c	31.2	4.8 ab	30.4	2.2 a	83	3 c	9	3 ab	8	1 a
Podzols	6	4.38	0.09 a	43.7	2.1 ab	33.3	3.6 c	43.4	2.5 b	42.0	1.6 a	75	5 c	15	5 ab	10	1 a
Acrisols	32	5.28	0.09 b	56.4	2.6 b	9.4	0.7 ab	18.1	0.8 a	39.1	4.1 a	6	1 a	25	3 b	70	4 c
Alisols	64	4.76	0.06 a	45.7	1.8 a	6.8	0.5 a	33.2	1.1 b	31.6	2.5 a	33	3 b	9	1 a	57	3 b
Luvisols and Lixisol	9	5.81	0.20 c	56.3	7.0 ab	9.9	1.3 ab	30.9	4.0 b	47.8	7.5 a	6	3 ab	15	7 ab	79	7 bc
Cambisols	71	4.95	0.07 ab	41.0	1.9 a	15.7	1.5 b	36.2	1.6 b	32.6	3.0 a	39	4 b	15	2 a	46	4 b
All	186	4.96	0.04	46.3	1.2	12.5	0.8	31.9	0.9	34.4	1.7	32	2	14	1	54	2
^†anova was applied after logarithmic transformation to normalize the dataset. Values with the same letters are not significantly different using a Tukey test (P < 0.05). AVE, average; SE, standard error.

Figure 2  Acidity and base saturation of the soils studied.

Figure 3  Mineralogical composition of the soils. (a) Relative abundances of mica, kaolin and expandable 1.4 nm minerals in clay fraction. (b) Relative abundance of expandable 1.4 nm minerals in clay fraction and DCB-extractable Fe of soils.

Figure 4  Characteristics of the cation exchange capacity (CEC) of the soils. CECmin/clay, CEC value per unit clay content; ECEC/clay, effective CEC (sum of exchangeable bases and Al) divided by clay content.

Figure 5  Relationship between mineralogical composition and chemical properties of the soils. Relationships between relative abundances of expandable 1.4 nm minerals in clay fraction and (a) CECmin/clay and (b) pH(H2O) of soils.

Table 3 Summary of the classification of the soils according to the World Reference Base

Sample group	No. samples	No. soils classified into different RSGs
		Andosols	Podzols	Alisols	Acrisols	Luvisols (or Lixisols)	Cambisols
							(Dystric)	(Eutric)
IDL	39	0	0	34	2	0	2	1
IDH	10	0	0	5	0	0	5	0
THL	40	0	0	5	20	3 (1)	9	2
THH	24	0	0	6	6	1	9	2
JPS	30	0	0	7	0	0	23	0
JPN	20	4	6	0	0	0	10	0
mafic	23	0	0	7	4	4	5	3
Total	186	4	6	64	32	9	63	8
RSGs, reference soil groups.

Watanabe , T , Funakawa , S and Kosaki , T . 2006 . "Clay mineralogy and its relationship to soil solution composition in soils from different weathering environments of humid Asia: Japan, Thailand and Indonesia . Geoderma , 136 : 51 – 63 .

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Soil Survey Staff . 2006 . Keys to Soil Taxonomy , 10th edn , Washington : US Government Printing Office .

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