Characterization of Andosols in Yakushima Island

Figures & data

Figure 1. Location of Yakushima Island.

Figure 2. Location of the five study sites.

Table 1. Morphological characteristics of the soils

Pedon	Layer	Depth (cm)	Color (Moist)	Field texture	Structure^†	Gravels rocks^‡	Hardness (mm)	Active aluminum- (Al)-test^§
ABR	Oi	+6–+3
	Oea	+3–0
	A	0–6	7.5YR3/2	CL	3 vfm–m cr	none	4	++
	AB	6–15	7.5YR3.5/4	CL	3 vf–c cr	none	5	+++
	BA	15–30	8.75YR4.5/6.5	CL	3 vf–m cr	none	8	+++
	Bw1	30–55	7.5YR5/7	LiC	3 f–c sbk	w–st b r f gr	10	++
	Bw2	55–75	7.5YR5/6	LiC	2 f–c sbk	none	10	+
	2C	75–100+	7.5YR3/1	LiC	massive	sl ls sa f sh	15	+
YSL	Oi	+2–0
	Al	0–6	7.5YR2/1.5	HC	3 v f–c cr	none	8	−
	A2	6–17	7.5YR2/2	HC	1 vf–m cr + 2 m sbk	none	10	+++
	AB	17–30	7.5YR4/3	SCL	2 m–c sbk	sl fg–g sa f gr	19	+++
	BA	30–42	7.5YR4/4	HC	2 m–c sbk	none	22	+
	Bwl	42–59	7.5YR5/6	HC	2 m–c sbk	w fg–g sa f gr + w fg sa f ah	16	+
	Bw2	59–76	8.75YR5/6	HC	massive	w fg–g sa f gr + w fg sa f ah	17	+
	Bw3	76–94+	10YR4.5/6	HC	massive	w fg–g sa f gr+sl lb sa f gr	17	+
HYH	Oie	+3–0
	A	0–8	7.5YR3/2	LiC	3 f–mcr	none	0	±
	AB	8–15	7.5YR3/3	HC	3 f–m cr + 1 m–c sbk	none	5	±
	Bwl	15–30	7.5YR4/3	HC	2 f–m cr + 1 m–c sbk	none	10	+
	Bw2	30–50	7.5YR4/4	HC	3 m–c sbk	st s sa f gr	12	+
	Bw3	50–70	7.5YR4/6	HC	2 c sbk	s1 1 s sa f gr	15	++
	BC	70–90+	7.5YR5/6	HC	2 c sbk	s1 la sa c gr+ s1 la sa f xe	15	++
YGG	Oie	+2–0
	OA	0–6	7.5YR2/2	CL	3 vf-m cr	none	3	−
	AB	6–14	7.5YR3/4	CL	2 vf–m cr + 2 m–c sbk	none	7	±
	Bwl	14–38	10YR4/6	CL	2 m–c sbk	w g sa f gr	14	+
	2Bw2	38–58	10YR5/6	SCL	1 m–c sbk	sl–w fg-g sr f gr	15	++
	2BC	58–68+	10YR7/4	SL	massive	sl–w fg-g sr f gr	17	++
MUD	Oi	+2–0
	Al	0–12	7.5YR3/2	LiC	3 vfm cr	none	10	+
	A2	12–24	10YR3/2	LiC	3 vfm cr	none	14	+
	A3	24–38	10YR2/3	LiC	3 vf–m cr + 2 f–c sbk	none	15	+++
	AB	38–50	10YR3/3	LiC	2 m–c sbk	w fg sa f ah	17	+++
	Bwl	50–68	10YR4/6	CL	2 m–c sbk	none	18	+++
	Bw2	68–85+	10YR3/4	CL	2 m–vc sbk	none	16	+++
ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake. ^†Description for structure: 1 = weak; 2 = moderate; 3 = strong; vf = very fine; f = fine; m = moderate; c = coarse; vc = very coarse: cr = crumb; sbk = subangular blocky.
^‡Description for gravels rocks: sl = slightly weathered; w = weathered; st = strongly weathered: fg = fine gravel: g = gravel: s = stone; ls = large stone; b = boulder sa = subangular; sr = subrounded; r = rounded: f = few; c = comon; gr = granite: ah = akahoya pumice: xe = xenolith of sandstone.
^§Active-Al test: +++, rapid and strong color development; ++ rapid color development; + rapid and weak color development; ±, weak color development; − no color development after sodium fluoride (NaF) addition to the soil samples on a filter paper, as an indication of the predominance of clays like allophene and imogolite.

Table 2. Particle size distribution and volcanic-glass concentration of the soils

Pedon	Layer	Particle size distribution (%)				Texture	Volcanic glass (grain%)
		Clay	Silt	Fine sand	Coarse sand
ABR	A	33.9	21.7	22.1	22.4	LiC	33.2
	AB	32.2	23.1	22.8	22.0	LiC	33.8
	BA	33.1	23.2	24.0	19.7	LiC	25.0
	Bwl	31.3	19.5	30.5	18.7	LiC	33.4
	Bw2	38.9	29.7	13.6	17.8	LiC	18.8
	2C	24.7	54.2	16.1	5.0	SiCL	2.4
YSL	Al	16.0	19.4	35.5	29.1	SCL	33.5
	A2	16.1	21.7	27.9	34.3	CL	49.6
	AB	14.6	11.1	36.8	37.6	SL	46.7
	BA	23.5	9.6	31.8	35.1	SCL	55.2
	Bwl	35.2	16.7	16.8	31.4	LiC	9.3
	Bw2	39.6	12.6	17.6	30.2	LiC	2.8
	Bw3	42.7	4.9	17.7	34.7	LiC	1.3
HYH	A	20.8	18.8	29.3	31.2	SCL	21.4
	AB	24.0	23.4	23.9	28.7	CL	21.6
	Bwl	26.2	23.6	21.3	28.9	LiC	27.2
	Bw2	29.4	23.3	13.5	33.8	LiC	20.3
	Bw3	33.1	18.4	18.0	30.6	LiC	10.2
	BC	37.0	15.4	20.8	26.8	LiC	11.8
YGG	OA	24.4	23.8	28.0	23.9	CL	34.8
	AB	19.2	15.8	30.7	34.3	SCL	35.0
	Bwl	20.2	21.1	24.1	34.6	CL	29.1
	2Bw2	27.3	11.5	23.8	37.3	SC	2.3
	2BC	21.1	10.5	29.0	39.3	SCL	0.0
MUD	Al	18.5	19.1	37.4	25.0	SCL	33.7
	A2	19.2	17.3	33.4	30.1	SCL	27.0
	A3	17.1	18.7	30.3	33.9	SCL	31.2
	AB	15.0	12.9	34.1	38.0	SCL	30.9
	Bwl	17.3	19.1	27.4	36.2	SCL	29.9
	Bw2	16.8	15.6	33.5	34.1	SL	53.6
ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake.

Table 3. Chemical properties of the soils

Pedon	Layer	pH		Total carbon	Exchangeable cation (cmol(+)kg^−1)						Base saturation (%)
		H2O	NaF	(g kg^−1)	Ca^2+	Mg^2+	K^+	Na^+	A1^3+	CEC
ABR	A	4.8	11.3	109	0.80	0.40	0.33	0.27	1.88	23.8	7.6
	AB	5.0	11.9	76	0.18	0.01	0.08	0.24	0.42	11.5	4.5
	BA	4.9	11.8	57	0.21	0.10	0.15	0.24	1.13	15.1	4.6
	Bwl	5.1	11.1	27	0.15	0.05	0.11	0.25	0.49	8.5	6.5
	Bw2	5.4	9.5	10	0.40	0.10	0.06	0.22	0.68	5.1	15.4
	2C	5.0	8.4	4	0.49	0.55	0.41	0.42	3.15	13.3	14.1
YSL	Al	4.5	9.1	135	1.72	0.89	0.41	0.30	3.65	26.0	12.8
	A2	4.7	10.2	78	0.49	0.28	0.19	0.22	2.55	18.0	6.6
	AB	5.2	11.3	27	0.09	0.00	0.03	0.17	0.31	13.8	2.1
	BA	5.1	11.2	23	0.07	0.00	0.05	0.12	0.22	4.4	5.3
	Bwl	4.8	10.0	15	0.06	0.00	0.07	0.11	1.23	6.0	4.0
	Bw2	4.8	9.7	10	0.06	0.00	0.08	0.09	1.92	6.3	3.8
	Bw3	4.9	9.9	7	0.06	0.01	0.08	0.08	2.10	5.9	3.8
HYH	A	4.6	7.9	124	4.21	0.92	0.32	0.20	2.45	22.6	25.0
	AB	4.7	9.3	64	1.02	0.29	0.23	0.19	2.35	15.4	11.2
	Bwl	4.7	10.5	51	0.40	0.12	0.18	0.17	2.38	12.1	7.1
	Bw2	4.8	10.4	35	0.23	0.19	0.12	0.14	2.34	11.9	5.7
	Bw3	4.8	10.1	21	0.16	0.11	0.10	0.10	2.33	9.8	4.8
	BC	4.8	10.4	16	0.15	0.02	0.08	0.10	2.15	8.7	3.9
YGG	OA	3.6	6.4	248	1.15	1.97	0.99	0.77	12.60	53.2	9.2
	AB	4.2	7.8	62	0.11	0.18	0.10	0.22	4.77	14.3	4.3
	Bwl	4.5	9.5	43	0.08	0.18	0.05	0.16	2.99	12.6	3.7
	2Bw2	4.6	10.2	13	0.04	0.00	0.03	0.11	1.70	5.3	3.5
	2BC	4.7	9.5	4	0.03	0.00	0.00	0.10	2.03	3.9	3.4
MUD	Al	4.6	9.4	103	0.33	0.49	0.54	0.28	3.59	15.8	10.4
	A2	4.7	9.6	104	0.29	0.43	0.48	0.31	2.90	15.5	9.8
	A3	4.9	10.0	84	0.19	0.25	0.25	0.23	2.35	12.6	7.3
	AB	4.9	11.3	58	0.11	0.09	0.13	0.20	1.17	6.9	7.7
	Bwl	4.9	11.8	43	0.08	0.01	0.08	0.18	0.42	5.4	6.6
	Bw2	5.0	12.0	36	0.06	0.03	0.03	0.01	0.24	5.0	2.4
ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake. H2O, water; NaF, sodium fluoride; Ca, calcium; Mg, magnesium; K, potasium; Na, Sodium; Al, aluminum; CEC, cation exchange capacity.

Table 4. Selective extraction data and phosphate-absorption amount of the soils

		Acid-oxalate (g kg^−1)				Pyrophosphate (g kg^−1)		DC (g kg^−1)
Pedon	Layer	Alo	Feo	Sio	Alo + l/2Feo	Alp	Fep	Fed	Alp/Alo	Fep/Feo	Feo/Fed	Phosphate- absorption (g kg^−1)
ABR	A	20.8	11.5	3.1	26.5	14.2	11.3	20.7	0.68	0.98	0.55	40.9
	AB	23.0	12.8	3.7	29.4	13.3	10.5	22.5	0.58	0.82	0.57	36.8
	BA	31.1	12.8	7.2	37.5	10.8	6.0	21.9	0.35	0.47	0.58	33.7
	Bwl	24.5	14.2	6.5	31.6	5.1	2.5	25.5	0.21	0.17	0.56	25.6
	Bw2	7.3	7.3	1.5	11.0	2.0	1.8	29.2	0.27	0.24	0.25	10.3
	2 C	2.0	1.1	0.2	2.5	1.0	1.1	17.7	0.52	1.03	0.06	8.5
YSL	Al	10.8	11.0	1.2	16.4	7.2	8.4	13.3	0.66	0.76	0.83	17.9
	A2	10.9	14	0.9	18.2	10.0	14.6	15.0	0.91	1.00	0.81	25.7
	AB	22.4	8.6	5.8	26.7	7.1	3.7	9.4	0.32	0.44	0.91	17.1
	BA	23.1	12.2	5.3	29.2	7.5	6.5	16.4	0.33	0.53	0.74	19.8
	Bwl	10.1	16.7	0.9	18.4	6.9	10.7	24.1	0.68	0.64	0.69	14.2
	Bw2	6.8	12.2	0.3	12.9	4.6	7.1	19.5	0.68	0.58	0.62	10.0
	Bw3	4.8	9.2	0.5	9.4	2.9	4.2	16.2	0.60	0.46	0.57	7.8
HYH	A	6.1	11.6	0.1	11.9	5.5	9.9	15.7	0.91	0.86	0.74	12.8
	AB	7.2	16.4	0.1	15.4	7.2	15.9	23.2	1.00	0.97	0.71	16.6
	Bwl	8.8	16.2	0.4	16.0	8.9	16.9	25.8	1.02	1.04	0.63	18.7
	Bw2	7.3	11.3	0.3	12.9	8.2	13.3	22.1	1.13	1.18	0.51	15.9
	Bw3	6.8	9.3	0.5	11.4	6.6	9.3	18.7	0.97	1.00	0.50	16.7
	BC	7.3	10.8	0.5	12.7	6.4	8.6	20.5	0.87	0.80	0.53	14.1
YGG	OA	6.3	5.5	0.1	9.0	6.0	4.8	8.6	0.96	0.87	0.64	13.9
	AB	5.2	17.3	0.1	13.9	4.0	13.3	23.7	0.77	0.77	0.73	14.7
	Bwl	8.0	19.9	0.1	18.0	7.0	17.1	24.7	0.88	0.86	0.81	19.3
	2Bw2	6.9	10.9	0.4	12.4	5.2	8.0	14.6	0.75	0.73	0.75	17.0
	2BC	2.7	2.8	0.4	4.2	1.5	1.7	4.9	0.55	0.60	0.58	5.8
MUD	Al	7.9	9.3	1.0	12.5	5.8	7.5	12.0	0.73	0.80	0.77	21.9
	A2	8.1	10.5	0.8	13.3	6.3	8.7	12.4	0.78	0.83	0.84	23.2
	A3	7.3	10.4	0.3	12.5	5.7	8.7	12.1	0.78	0.84	0.86	20.2
	AB	9.2	11.0	0.6	14.7	7.7	9.4	13.7	0.84	0.85	0.80	26.0
	Bw1	14.7	13.2	2.1	21.3	9.3	9.7	15.6	0.63	0.73	0.85	31.6
	Bw2	20.1	13.5	4.2	26.9	7.9	6.5	14.9	0.39	0.48	0.91	24.3
ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake. Alo, acid-oxalate extractable aluminum (Al); Feo, acid-oxalate extractable iron (Fe); Sio, acid-oxalate extractable silicon (Si); Alp, pyrosulphate extractable Al; Fep, pyrosulphate extractable Fe; Sip, pyrosulphate extractable Si; DC, dithionite-citrate; Fed, DC extractable Fe.

Figure 3. Relationship between volcanic glass concentration and acid-oxalate extractable aluminum (Alo) concentration of the soils. ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake.

Figure 4. Relationship between volcanic glass concentration and acid-oxalate extractable silicon (Sio) concentration of the soils. ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake.

Figure 5. X-ray diffraction patterns of the clay samples from surface horizons. ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake.

Figure 6. X-ray diffraction patterns of the clay samples from selected subsurface horizons. ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake.

Table 5. Clay mineralogy of the soils

Pedon	Layer	Vr	Sm	HIV/HIS	Ch	Mi	Mi-Vr/Mi-Sm	Kt
ABR	A	++	−	+++	+	−	+	++
	AB	++	−	+++	+	−	+	++
	B A	++	−	+++	+	−	+	++
	Bwl	+	−	++++	−	−	−	+
	Bw2	++	−	+++	−	+	++	++
	2 C	+	−	+++	−	+	++	++
YSL	Al	++	+	++	−	++	+	++
	A2	++	−	+++	+	++	+	++
	AB	++	−	+++	+	+	+	++
	BA	++	−	++	+	+	+	++
	Bwl	++	−	+++	+	+	+	++
	Bw2	++	−	+++	+	+	+	++
	Bw3	++	−	+++	+	+	+	++
HYH	A	++	−	+++	+	+	++	++
	AB	++	−	+++	+	+	++	++
	Bwl	++	−	+++	+	+	++	++
	Bw2	+++	−	++	+	+	++	++
	Bw3	++	−	+++	+	+	++	++
	BC	++	−	++	+	+	++	++
YGG	OA	+	++	++	−	+	++	+
	AB	++	−	+++	+	+	+	++
	Bwl	+++	−	+++	+	++	+	+
	2Bw2	+++	−	++	−	+	+	+
	2BC	++++	−	+++	−	+	−	−
MUD	Al	++	−	+++	+	+	++	++
	A2	++	−	++	+	+	++	++
	A3	++	−	++	+	+	+++	+++
	AB	++	−	++	+	+	++	++
	Bwl	++	−	++	+	+	++	++
	Bw2	++	−	++	+	+	++	++
ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake. Vr, vermiculite; HIV/HIS, hidroxy-interlayerd vermiculte and/or smectite; Ch, chlorite; Mi, mica; Mi-Vr/Mi-Sm, interstratified Mica-vermiculte and/or Mica-smectite; Kt, kaoline minerals. −, not detected; +, 1–10%; ++, 10–35%; +++, 35–60%; ++++, 60%<.

Table 6. Soil classification

Pedon	USCSJ 2nd	WRB
ABR	Typic brown Kuroboku soil	Fulvic Andosol (Acroxic, Dystric)
YSL	Typic non-allophanic Kuroboku soil	Vitric Andosol (Acroxic, Dystric)
HYH	Typic non-allophanic Kuroboku soil	Vitric Andosol (Dystric)
YGG	Typic non-allophanic Kuroboku soil	Vitric Andosol (Dystric)
MUD	Non-allophanic brown Kuroboku soil	Umbric Vitric Andosol (Acroxic, Dystric)
ABR; Anbo-gawa right side; YSL, Yakusugi-land; HYH, Hanayama-hodou; YGG, Yodogogoya; MUD, Miyanoura-dake. USCSJ 2nd, Unified Soil Classification System of Japan - 2nd Approximation; WRB, World Reference Base for Soil Resources.