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Studies on genesis and classificationof soils in warm-temperate region ofSouthwest JapanShizuo Nagatsuka aa National Institute of Agricultural Sciences , JapanPublished online: 22 May 2012.

To cite this article: Shizuo Nagatsuka (1972) Studies on genesis and classification of soils inwarm-temperate region of Southwest Japan, Soil Science and Plant Nutrition, 18:4, 147-154,DOI: 10.1080/00380768.1972.10433287

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(Soil Science and Plant Nutrition, Vol. 18. No. 4, p. 147-154, 1972)

STUDIES ON GENESIS AND CLASSIFICATION OF SOILS IN \VARM·TEMPERATE REGION OF SOUTHWEST JAPAN

Part 3. Some Features in Distribution and 1\fode of Existence of Free Iron and Aluminium Oxides in the Soil Profile

Shizuo NAGATSUKA

National Institute of Agricultural Sciences, Japan RECEIVED JANUARY 26, 1972

The free sesquioxides in the soil may exist both in the crystalline and amorphous forms. The amount and the relative distribution of these forms within the soil profile can have a most important bearing on the physico­chemical properties of the soil, on the inter­pretation of soil genesis and on studies con­nected with Intensity and condition of weather­ing (1, 2).

It is well known that the content of acid .oxalate soluble iron clearly characterizes Pod­.zols and formation of Brown Forest soils (Braunerden) (3). On the other hand, lessivage (illimerization) is characterized by the fact that dithionite soluble iron has very close, highly significant, positive correlation with clay content, which indicate co-migration of iron with clay minerals (4). URUSliADSE (5) showed in his study on Brown Forest soils of Georgia that each sub-type of the Brown Forest soils has its own characteristic distribu­tion pattern of oxalate- and dithionite-soluble iron within the soil profile. BLUME and SCIIWERTMANN (6) proposed a concept of " activity ratio" which is defined as the ratio .of oxalate-soluble Iron to dithionite·soluble iron, and showed typical ranges of the ratio for the main types of soil horizons of the various great soil groups of the humid tem· perate region. STONEHOUSE and ARNAUD {7) reported a similar investigation with regard to Chernozemic, Solonetzic, Luvisolic, and Gleysolic soils of Saskatchwan, Canada. A

147

study of this kind has been carried out by Y AMDE and KUROTORJ (8) for Brown Forest soils of Amagi and Takao regions, in Japan. The purpose of this paper is to make a contribution for the characterization of the so~ called "Yellow-Brown (Forest) soils" in the warm-temperate region in comparison with Red soils in the same region and Brown Forest soils in the cold-temperate region of Japan,

MATERIALS AND METHODS

As representative soil profiles under lucido­phyllus forest climate in the warm-temperate region, five Yellow-Brown Forest soils on hilly areas, four Red soils on foothills and higher terraces, and four Yellow-Brown soils on mid· dle and lower terraces in the Tokal region of Southwest Japan were used. Chemical and mineralogical properties of these soils have already been reported in previous papers (9, 10). For comparison, four Brown Forest soils in the Kanto-Tosan region of Central Japan were also employed,

The climate of the localities where the Drown Forest soils are distributed is charac• terized by a mean annual temperature of 8,6°C, annual precipitation of 1,849mm, wnrmth·in~ dex of 66. 9°C and coldness-index of -23. 6"C, belonging to the northern temperate deciduous broad-leaved forest climate, Whereas the region where Yellow-Brown Forest, Yellow-Brown and Red soils are distributed is characterized

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148 S. NAGATSUKA

Table 1. Soil samples and site characteristics

Symbol Locality Vegetation Topography Altitude Parent rock or (m) material

Brown Forest soils Do Chichibu Fagus crenata·Tsuga Sieboldii ridge 1,180 shale De Yashajintoge Abies homolePii·Clethra barbinervis range-flank slope 1,500 siliceous shale Do Chichibu Fagus crenata·Abies firma range-flank slope 1,160 phyllite Bs Chichibu Fraxinus Spaethiana depression 1,150 phyllite

Yellow-Drown Forest soils YDA Kamewaritoge Pinus densijlora·Bu:xus microPhylla backslope 260 serpentinized

var. suffruticosa gabbro YDII Mt. Ubusan Pinus densijlora-Cydobalanopsif shoulder slope 320 gabbro

acuta YDc Ise shrine Cinnamomum Camphora· shoulder slope 130 diabase

Cyclobalanopsif glauco

YBo lhara Pinu1 densijlora-Miscanthus gentle hillslope 100 tuffceous sand· sinensis stone

YB/R Daifukuji· Pinus densiflora·Quercus serrata headslope 70 slope deposit Kltayama with Sasa

Red soils R-1 Fukunaga Pinus densijlora·Cinnamomum interfluve 45 terrace sediment

Camphora

R-2 lhara Pinus densijlora·Quercus serrata higher terrace 42 II

R-3 Daifukuji Shiia sp.-Cydobalanopsis sP.•Pinuf higher terrace 55 II densijlora

R-4 Honzaka CyclobalanoPsis sp. with bamboo higher terrace 30 II

Yellow-Brown soils ---------·-Y-1 Kitahara evergreen scrub with oak middle terrace 20 II

Y-2 Ushi Rhododendron sp,.PJ'nus dens•'flora middle terrace 15 II with Sasa

Y-3 Oaaki waste land with weeds lower terrace 5 II

Y-4 Shlniohara Pinus densiflora·Rhododendron sp. lower terrace 15 II -----------

by a mean annual temperature of 15. goc, an· nual precipitation of 2,075 mm and warmth· index of 134. 3°C, belonging to the northern warm-temperate lucidophyllus forest climate. Other soil forming factors of each locality are shown in Table 1. The symbols, Bo, Bo, Bo, and Bt>, indicate dry (gentle slope type)·, slightly dried·, moderately moist·, and slightly wet Brown Forest soils in OIIMASA's clas· sificatlon (11), respectively. YB ... indicate dry Yellow-Brown Forest soils (steep slope type) and YBo, Yllo, YBo correspond in moisture regime to Bo, Be, and Bo, respectively (12). Red soils belong to the Red member of the Red·

----~-- ----

Yellow soils. Yellow-Brown soils are consider .. ed to belong to the Yellow-member of the Red-Yellow soils (13), but the author prefers to use the term "Yellow-Brown soil" since these soils are different from the Red soils in degree of weathering (10).

The soil samples used were taken from each horizon of the representative soil profiles. Extraction of free sesquioxides from air-dried fine earth ( <2 mm) was carried out using acld ammonium oxalate (TAMM's reagent A) (14) and dithionite-citrate·blcarbonate (15), sepa· rately. In each extraction, the sample was treated twice with the extractant. The ex-

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Studies on Genesis and Classification of Soils in Warm-Temperate Region of Southwest Japan 149

tracts were then treated with a mixture of acids (HN08 : H2S04: IIC 104 = 10: 1 : 4) and were evaporated to dryness in order to destroy organic matter. The residues were then dis­solved in dilute HCI solution. Fe and AI in the solution was colorimetrically determined using ferron according to the method describ­ed by DAVENPORT (16) and BELYAEVA (17). The amounts of iron and aluminium oxides were expressed in percentages on an organic matter free dry basis, in order to avoid rela· tive or apparent change caused by mere ac­cumulation of organic matter (carbonates are not contained in these soils). Total iron was determined colorimetrically using o-phenathro· line according to the method described by SHAPIRO and BRANNOCK (18).

RESULTS AND DISCUSSION 1. Depth function of free sesquioxides Distribution of acid ammonium oxalate solu·

ble iron (Feu) and aluminium (Alu), and that of dithionite-citrate-bicarbonate soluble iron (Fea) and aluminium (AI~) within the soil pro­tile is shown in Fig. 1.

Brown Forest soils. In the profiles of Bo and Do, the amount of Feo, Fea, Ala, and Al4 is the lowest in the C horizon and increases gradually until it reaches a maximum in the upper A1 horizon. This tendency of distribu­tion agrees with that observed in Braunerden of Central Europe as reported by SCHLICHTING and BLUME (4). While the profile of Do shows a decrease in the amount of FeJ, Ala, and Ala in the A1 horizon, indicating the presence of slight podzolization. The reverse tendency observed in BE may be due to enrichment of iron and aluminium in the subsoil horizons by lateral movement of soil solution and/or a supply of fresh parent material at the top horizons from upslope.

Yellow-Drown Forest soils. In contrast to the Brown Forest soils, the amount of Fea and AI., in the Yellow-Brown Forest soils is as little as about 1%. The tendency of upward increase in these values is not as clear as in the case of Brown Forest soils~ and the amount of Fea and AI., shows almost no difference among the subsoil horizons below the A1 horl·

zon, On the other hand, the amount of Fea and Aid, especially of Fe~, shows a tendency to increase downwards in the Yellow-Brown Forest soils except YBo, which tendency is reverse to that of the Brown-Forest soils. The amount of Fea and Ab is proportional to the clay content in some cases (YBo and YBo), but is not proportional in the other cases (YBA and YBo}, and shows no definite trend.

Yellow-Drown soils. The amount of Fea and Ala in the Yellow-Brown soils is still less than that in the Yellow·Brown Forest soils, and is almost constant throughout the profiles. The amount of Fed and AI~ shows a slight down­ward increase. The distribution pattern of sesquioxides of the Yellow-Brown soils is simi· lar to that of the Yellow-Brown Forest soils.

Red soils. The main feature of Red soils is characterized by the fact that the amount of Fea is far greater than that of Feo. The amount of Feo and Ala in Red soils is very small (less than lro) and Is almost constant throughout the profile as in the case in the Yellow-Brown soils. Two types of distribution of Fea and Ala are observed in Red soils. One is an upward increasing type as shown by R·1 and R-3, and the other is a type which shows almost constant content below the A horizon (R·2 and R·4). The former type of distribution may suggest· that the upper part of the soil profiles R·1 and R·3 has been truncated ·by erosion. The buried Red soil beneath the Yellow-Brown Forest soil as shown by YB/R shows a downward increase in the amount of FeJ and Ala in the upper part and upward increase in the lower part.

2. Relationship among oxalate-, dUhionitc­soluble iron and total iron

Many investigations, concerning the solubil· lty of iron compounds, to several extractants have shown up to now the following findings: TAMM's reagent A, and similar acid oxalate, dissolve In the dark, adsorbed iron (19), iron combined with humus (19), amorphous ferric hydroxide (20, 21, 19, 1, 6), magnetite (20, 21), iron phosphate (20, 21) and a part of goethite (1). On the other hand, cltrate-dithionite·bicar· bonate dissolves most of the goethite and hematite (15, 1) in addition to the acld oxalate soluble iron compounds mentioned above.

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150

0 t-F H At

60

100 em

82

c

50 c

100 em

60

100 em

R

Ct

Ca

2 4

Y-1

1 0 20 30 40 %Clay

S. NAGATSUKA

2 4 6 8 %L F•H

~········-At ............ -·· Al

Bo 8t

82

50 %Clay

10 20 30 %clay

f"" ·•···

...... ·~" ......... Fe203 } Oxalate soluble ...... - Al203

... , I ~ I I R-4

, ~ I

\ ill I !I' \ ;~ I

PI i

- Fe2D3} Citrate-dithionite _. Al 203 soluble

Total carbon ·-·-·-· Clay

0 20 3 0 40 60%CI 4 ay 8 'Y. 2 4 6 8 'Y.

' AI I I \ . I . BC I I \ '· I/ '· .. / _,/c, /

.I" C2 V-3 i 10 20 30 40%C av 10 20 30 40 roclav

1~111'. 1. Distribution of free aesquloxides, clay, and total carbon in the soil profiles Free iron and aluminium oxides are expresaed as Fe20s. AI,Oa % on organic matter free dry basis.

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Studies on Genesis and Classification of Soils in Warm-Temperate Region of Southwest Japan 151

'fable 2. Relation between free sesquiox.ides and other properties of soils

y

Feo Alo Fed Alu Feo Alo Fed Aid

Fed-Feo Ald-Flo Fe<t-Fe<>

Fet Feo Fed

T-C:

1.0

0.9

X

T-C• T-C T-c T-C Clay Clay Clay Clay Clay Clay

Clay

Fet Fet

Total carbon.

0.8 ···-;;···------·--···1

0,7

I 0.6

o1J ""'""' 0.5

. .. . .

'

' .0.. l . : 0.4. •• j

~ ,. .. ~,.,.,.. ... ~ .. ~,. .. ,,.,;-"'~~41\l,,.n.,. ... -,..,

0.3 ••• . . . () .. .. ,. 'f' A ... 0.2

•• 4~

A •• JrM X A J( .... .. . 0.1

Correlation coefficient

( r)

0.570 0.426

-0.097 0.435

-0.172 -0.888

0.585 0.051 0.639 0.600

0.706

0.296 0.852

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Feu- Fee Fe_t_

Fhr. 2. Plot of the ratio Feo/Fed 111. the ratio Fe~· Feo/Fet for Brown Forest, Yellow-Brown Forest, Yellow-Brown, and Red soils 0 Brown Forest soil, e ·Yellow· Brown Forest soil, X Yellow•Drown soil, A Red soil.

Regression equation n Y =aX+ b

0.107 + 0.701 78 0.108 + 0.850 83

-0.109 + 5.754 83 0.126 + 1.434 83

-0.007 + 1.225 83 -0.020 + 1.690 83

0.131 + 1.606 83 0.003 + 1.651 83

0.139 + 0.353 83 0.023 0.039 83

0.008 + 0.116 81

0.028 + 0.697 81 0.441 + 0.280 81

Consequently, the difference between citrate­dithionite-bicarbonate soluble iron (Fea) and acid ammonium oxalate soluble iron (Feo) may be used as an approximate measure for crystal· line free iron oxides, and Feo may be used as a measure for the amorphous portion of the free iron oxides unless significant amount of magnetite and iron phosphate is present .

The ratio Fe,,fFeJ has been used as a rela· tive measure of the degree of aging or crystal· linity of free lron oxides(6). However, as BLUME and SCHWERTMANN (6) pointed out, such values are strictly valid only for a comparison of horizons within the same profile or for soils from the same parent material. On the other hand, as shown in Table 2, the amount of Fea shows relatively high, positive correla­tion (r=O. 852) with the amount of total iron (Fe~) throughout all the samples analyzed, whereas the correlation between Feu and Fe1

is very low. This may suggest that the amount of Fe4 ts greatly influenced by total iron content of the parent materials.

The ratio (Fed-Feo)/Fe, also shows relatively high, positive correlation (r=O. 706) to clay content, which indicates that the ratio of crystalline free iron oxides to total iron con·

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152

Soil

Profile distri-but ion

-·

S. NAG.t\TSUKA

Table 3. Characteristic features in distribution and forma of free sesquioxides for each group of soils

Brown Forest soils Yellow-Br~wn Forest I Yellow-Brown soils I SOliS Red soils

Feo A,;;::A,;;:Ba>Ba>C A1~B1=Ba=Ba=C I At=BC, BaSC A1= Bt= Ba= Ba= C Alo A,SA~;;: Ba;;: Ba> C A,sn,= Ba= Ba= c A•=BC, BaSC A,=D•=Ba=Ba=C Fe a A,SAa;;:Ba>Ba>C A ,s B ,s BaS B ,;;: C A,SB C. BaSC r·> a.> •·> •·> c or

A,<B,= Ba= Ba>C Ald A.SAa;;:Ba> Ba>C A ,s B ,s B aS B a> C A ,s B C , B aS C fA•=D•>Da>Ds>C 1 or

A .s B Is B .;;: D .;;: c .M.*of F~d_-Feo

Fe, 0.19-0.26 l 0.27-0.34 I 0.25-0.40

I 0.47-0.57

P.M. *of __ FFeo_ ea , ___ o_._4o_-_o_. 5-4--;---0_._14_-_o_. 20----'~-- o. 15-o. 29 0.08-0.10

Dominant form of free iron mainly amorphous oxides

crystalline forms predominate over amorphous forms

mainly crystalline forms

* Confidence interval for the popuration mean with confidence coefficient 0. 95.

60

50

10

Red soil

Yellow~ Brown Forest soil &

Yellow-Brown soil

Fe. Fed

1.0

Flar. 3. Relative frequency distribution curves of the Fe.,;Fert ratio

tent increases with the increase of clay con· tent as the degree of weathering advances, Hence, the ratio (Fea-Feo)/Fel may be used as a relative measure of the degree of weather· ing accompanied by aging or crystaUization of free iron oxides for soils from different parent

materials. In Fig, 2, the values of the ratio Feo/Fea

are plotted against the ratio (Fed-Feo)/Fe, obtained from all the horizons of the soil profiles. From Fig. 2 a general trend is rec· ognized showing that the plots are distributed in three different domains of Brown Forest soils, of Yellow-Brown Forest and Yellow· Brown soils, and of Red soils. Furthermore, as shown In Fig. 3, relative frequency distribu· tion curves of Fea/Fed for Brown Forest soils, Yellow-Brown Forest and Yellow-Brown soils, and Red soils differ from one another.

The results of t-testing in Table 3 show that the confidence Intervals for the population means with confidence coefficient 0. 95 of the ratio (Fe~~-Feo)/Fe, range 0. 19-0. 26 for Brown Forest soils, 0. 27-0.34 for Yellow-Brown For• est soils and 0, 47-0. 57 for Red soils, and that those of the ratio Feo/Fe<l range 0. 40-0. 54 for Brown Forest soils 0, 14-Q, 20 for Yellow Brown Forest soils and 0. 08-0.10 for Red soils. These confidence intervals do not overlap with one another, indicating the presence of significant difference among these groups of soils. While the confidence intervals for the population means of the ratio (Fea-

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Studies on Genesis and Classification of Soils in Warm-Temperate Region of Southwest Japan 153

Feo)/Fel and Feo/Fe.t with confidence coefficient 0. 95 for Yellow-Brown soils are 0. 25-0. 40 and 0.15-0. 29, respectively, which overlap with those for Yellow-Brown Forest soils. This suggests that Yellow-Brown Forest soils and Yellow-Brown soils belong to the same group that have these properties.

The above results, together with the fact shown in the previous paper (10) that the Yellow-Brown Forest and the Yellow-Brown soils are in the less advanced stage in the weathering sequence relative to the Red soils, may support the view that considers Yellow· Brown (Forest) soils as an independent genetic soil type different from Red soils and Brown Forest soils.

CONCLUSIONS AND SUMMARY

From the foregoing the following conclusions can be made:

l) Brown Forest soils occurring in the cold· temperate deciduous broad-leaved forest region are high in acid oxalate soluble iron (Feo) and aluminium (Aio) relative to Yellow-Brown Forest, Yellow-Brown, and. Red soils found in the warm-temperate lucidophyllus forest region. The amount of Feo, Alo, dithionite-citrate• bicarbonate soluble iron (Fed) and aluminium (Ald) shows a general tendency to increase upwards in the Brown Forest soils. This tendency is similar to that observed in Drau· nerden of Central Europe.

2) Yellow·Brown Forest soils are rather low in Feo and Alo content. The tendency. that Fea and Ala increase upwards is not con· spicuous as compared with the Drown Forest soils. While the amount of Ffd and Aid of Yellow-Brown Forest soils shows a general tendency to increase downwards, but the co-migration of iron with clay minerals is not clearly defined. Yellow-Brown soils are similar to Yellow-Brown Forest soils in these respects.

3) Red soils are very low in Feo and Alo. The distribution of Feo and AI, within the profile is almost constant in Red soils. The main feature of Red soils is characterized by the amount of Fed which is far greater than that of Feo.

4) The ratio (Fea-Feo)/Fel as well as the ratio Feo/Fec1 are helpful to differentiate Drown Forest, Yellow-Drown Forest, and Red soil, from each other. From the values of these ratios, it can be inferred that amorphous free iron oxides predominate in the Brown Forest soils and crystalline free Iron oxides are dominant in the Red soils, while YeUow•Brown Forest soils are inbetween. It also suggests that Yellow-Drown Forest and Yellow-Brown soils belong to the same group is defined by these properties.

Acknowledgement. The author wishes to express his gratltudes to Assistant Professor Dr. Y. Kato, Shizuoka University and Mr. K. Endo, Tokyo Unl· versity, for their Invaluable guidances and kind helps in soil sampling. The author is also grateful to Mr. Y. Marumo for his help ln the chemical analyses.

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1) GORBUNOV, N.I., DtYADEVICH, G.S., and TUNIK, D.M., Pochvovedenie, No. 11, 103 (1961)

2) MITCHELL, B.D., FARMER, V.C., and McHARDY, W.],, Ad van. Agron., 16, 327 (1964)

3) LUNDBLAD, K., Soil Sci., 37, 137 (1934) 4) ScHLICHTING, E. and Dt.UME, Il.P., Z. P/1an·

zenerniJhr. Diing. Dodenk., 96, 144 (1962) 5) URUSHADSE, T.F., Pochvovedenie, No. 1, 48

(1967) 6) BLUME, H.P. and ScHWERTMANN, U., Soil Sci.

Soc. Am. Proc •• 33, 438 (1969) 7) STONBHOUSil:, U.D. and ARNAUD, R.J, St., Can.

J. Soil Sci., I'll, 283 (1971} 8) YAMBE, F. and KUROTORI, T., Nippon Dojo­

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11, 154 (1971) 10) NAGATSUKA, S., ibid., 18, 65 (1972) 11) OuMASA, M., Forest Soils of Japan, Rept. 1,

Govt. Forest Exp. Stn. (Tokyo), (1951) 12) ENDO, K., Trans. 75th Mtg, Jap, For, Soc.

146 (1964) 13) KANNO, I., Rap. VI" Congr. Int. Sci. Sol., E 99

(1956) 14) TAMM, 0., Meddcl. /ran Staten• Skogl/drsOkt­

anslall, 21, 1 (1932-1934) 15) MEIIRA, O.P. and JACKSON, M.L., "Clays and

Clay Minerals," Pergamon Preas, New York, Vol. '1, p. 317 (1960}

16) DAVENPORT, W.H., Anal. Chem., 21, 710 (1949)

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154 S. NAGATSUKA

17) BELYAEVA, N.J., Pochvovedenie, No. 2, 106 (1966)

18) SUAPIRO, L. and BRANNOCK, W.W., U.S. Geol. Survey Circular, 165 (1952)

19) ScHWERTMANN, U., z. Pjlanzenerniihr. Dung.

Bodenk., 84, 194 (1959) 20) HARADA, M., J. Agr. Chem. Soc. Japan, U.,

1032 (1936) 21) HARADA, M., ibid. 13, 383 {1937)

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