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DETAILED SOIL SURVEY OF SUNGAI MUPUT KIBA AREA, MODEL FOREST MANAGEMENT AREA (ANAP F.R.)

(ITTO Project PD 14/95 REV. 2 (F) - Model Forest Management Area (Phase 11»

JOHN SABANG (SOIL SURVEYOR)

International Tropical Timber Organisation Unit (ITTO), Forest Department Kuching, Sarawak, Malaysia

OCTOBER - DECEMBER 1996

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CONTENTS

1. Introduction

2. Survey Method

3. Vegetation and Landuse

4. Geology and Landform

5. Soil Classification and Mapping Unit

6. Soils

7. Soil Suitability

8. Suitability Classes for Landuse Options in Forestry Application

9. Landuse in Forestry Application

10. Correlation Between Soil and Terrain and the Landuse Options

11. Conclusion

12. References

Appendix: Soil Profiles Description

Maps attached:

Map 1 Map 2 Map 3

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Soil Examination Plan Soils and Terrain Site Suitability

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1. Introduction

An area located between Sungai Muput Kiba and Sungai Lemai, within the Model Forest Management Area, Anap Forest Reserve was identified for a detail soil survey with the objective of setting up 10 hectares of shifting agriculture area and logged over forest as an experimental forest plantation plot. The experiment will also include enrichment planting and Silviculture treatment of the selected plot. The location of the area is shown in Figure 1.

The area selected is along the main trucking road linking Zedtee's Sekawi camp to the south and the Sangan logpond to the north. It has been recommended that such area be brought back to timber production as proposed in the Plan for Conversion of Forest Areast

. Experimental plantings and Silviculture treatments trials are required in the Model Forest Management Area before such effort can be implemented by agencies or companies having an interest in sustainable resources production.

The field work was carried out from 17 October until 2 November 1996 with assistance of Forest Guard Yazid Kalbi and Labourer Colin Imat from the Soil Research Unit, Research Branch, Department of Forestry Sarawak. The size of area surveyed is about 160 hectares.

2. Survey Method

A base map at the scale of 1 : 5,000 was prepared by the enlargement of a computer digitised 1 : 50,000 topographic map which was also incorporated with layout of the main trucking road obtained using the Global Positioning System. The trucking road was used as a baseline for planning the cut-lines (rentises).

The cut-lines were spaced about 100m and along each cut-line the soil and site features were recorded. The soils were examined by augering down to 1 m with an Edelman auger at 100m interval along each cut-lines. Certain sites were chosen for soil pits for detailed examination of the dominant soil types. Soils samples were collected from each pit for laboratory analyses.

After the field work was completed and the data compiled Soil Examination Plan which also shows the vegetation/landuse was prepared (Map 1). The soils and terrain information was then incorporated and synthesised to produced the Soils and Terrain map (Map 2). Based on the soils and terrain information and with the knowledge on drainage conditions, flooding and erosion hazard, the Site Suitability map was finally compiled (Map 3).

t 10-Year Development Plan for the MFMA - Sarawak 1996-2006, Forest Land Use and Management Plans, Training. Research and Development and Demonstrations, The Government of the Federation of Malaysia, State Government of Sarawak - Forest Dept.. International Tropical Timber Organisation. Kuching, November 1995.

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Figure 1:

MAP Showin in MFMA

Location of the area

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3. Vegetation and Landuse

The vegetation and landuse of the Area is shown on Map 1. The shifting agriculture areas which are under 2 to 4 years stages of fallow are located along the fringe of the trucking road and the 1 year stage of fallow is located at the northern brink of the surveyed area. Beyond the shifting agriculture area, is the primary forest that has been logged for the last 1 to 2 decades ago.

4. Geology and Landform

The land is underlain by sandstone, siltstone, shale with intercalation of marlstone, conglomerate and acid volcanic existing as part of the Tatau Formation formed during the Eocene - Oligocene age. The soils derived from this formation are mainly clayey Merit Series, fine loamy Bekenu Series and their variant the Kapit Series.

The landform of the area can generally be described as steep and strongly dissected hills. The Area is drained by the Sungai Muput Kiba at the southern portion and the northern portion by a tributary of the Sungai Lemai. Due to the poor construction of culvert along the trucking road the aforementioned tributary has developed into a deep extended pond.

5. Soil Classification and Mapping Unit

The soil survey that was conducted has an observation density of approximately 1 per hectare. The soil examination plan with a scale of 1 : 2,000 is shown on Map1.

The Soils are classified at series level and 12 soil series have been recognised and described. The soils and terrain information are combined to form the soil mapping unit. The soils types are grouped either as single soil series or as association of two or more soil series.

The soils identified comprised mainly of Merit, Jakar, Bekenu, Sarikei and Nyalau series of the Red Yellow Podzolic Soils, Kapit and Tutoh series of the Skeletal soils. The Red Yellow Podzolic soils also has a minor amount of Tukau and Sabangan series. The narrow fringe along the Sungai Muput Kiba consisted of the Bemang series of the Alluvial soils.

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6. Soils

6.1 Red Yellow Podzolic Soils

6.1.1 Merit Series (Mrt)

The Merit Series soils of the Merit family are the clayey texture Red Yellow Podzolic group with colour hue of 10 YR within 50cm of the surface. They are derived from argillaceous sedimentary rock, mainly shale .. They are the fourth most dominant soil and are associated with the Jakar and Bekenu Series soils. The soil profile has a brownish yellow A horizon above a yellow B horizon. Shale fragments is commonly found in the subsoil. The Merit Series soils are further classified into moderately shallow phase, 50 to 75cm (Mrt 1), moderately deep phase, 75 to 100cm (Mrt 2) and deep phase> 100cm (Mrt 3). The Merit Series soils are mainly of the moderately shallow and moderately deep phases. Description of 2 Merit Series soil profiles are given in the appendix.

6.1.2 Jakar Series (Jkr)

The Jakar Series soils are also of the clayey Red Yellow Podzolic group and similar to the Merit Series except for a redder soil colour hue of 7.5 YR to 5 YR within 50cm from the surface. They are however less extensive than the latter. The soil profile has a yellow A horizon over reddish yellow B horizon. The Jakar Series soils are also classified into phases likewise.

6.1.3 Bekenu Series (Bkn)

The Bekenu Series soils are fine loamy Red Yellow Podzolic group with colour hue of 10 YR within 50cm of the surface. The Bekenu soils are more extensive than the above Merit family soils. The profile has a brownish yellow A horizon over a yellow B horizon. Weathered rock fragements are common in the subsoil which increases with depth. Soil phases is similar to the Merit Family soils. The moderately shallow phase is the most common. Description of 2 Bekenu Series soil profiles are given in the appendix.

6.1.4 Sarikei Series (Srk)

The Sarikei Series soils are also of the fine loamy Red Yellow Podzolic group similar to the Bekenu soils sxcept for a redder soil colour hue 7.5 YR to 5 YR within 50cm of the surface. The soil profile has brownish yellow A horizon over reddish brown B horizon. Depth phases are similarly identified as in the Bekenu soils. They are however minor in occurrence.

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6.1.5 Tukau Series (Tuk)

The Tukau Series soils are also of the fine loamy Red Yellow Podzolic group belonging to the Bekenu Family. They developed on old alluvial deposit as on old river terraces. The presence of stoneline of rounded sandstone in the subsoil indicated their alluvial origin. They are confine to the narrow strip along the Sungai Muput Kiba and also associated with the Bekenu soils on an old river terrace.

6.1.6 Sabangan Series (Sbn)

The Sabangan Series soils are similar to the Tukau soils except for their coarser texture. They thus belong to the Nyalau Family, of the coarse loamy Red Yellow Podzolic group. The soil is confined to a small area neighbouring the Tukau soils.

6.1.7 Nyalau Series (Nyl)

The Nyalau Series soils are of the coarse loamy Red Yellow Podzolic group developed on sandstone. The soil profile has brownish yellow A horizon over yellow B horizon. Depth phases are similarly identified as in the Bekenu soils. They are of very limited occurrence found isolated.

6.2 Skeletal Soils

6.2.1 Kapit Series (Kpt)

The Kapit Series soils are of the Skeletal group having more than 50 percent rock fragment or soft weathered bedrock within 50cm of the surface. They are the shallow variant of the Red Yellow Podzolic soils and are more extensive in

1 occurrence. Significant amount of the Kapit soils were observed as man made .1 (. such the of truncation and deposition of soil on and alongside feeder roads and

skid trails. The rock fragement are either shale or a combination with sandstone. Description of 2 Kapit soil profiles are given in the appendix.

6.2.2 Meluan Series (Mln)

The Meluan Series soils are of the Skeletal group where hard bedrock is encountered within 50cm fr'bm the surface. They are mainly underlain by siltstone or sandstone at the toe of slopes and are of limited occurrence.

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6.2.3 Tutoh Series (Tth)

The Tutoh Series soils are similar to the Kapit soils except that the soils are derived from material previously slumped down from steep slopes with many angular rock fragments occuring within 50cm from the surface.

6.3 Alluvial Soils

The Bemang (Bmg) Series soils are of the Alluvial group with fine loamy texture derived from accreting riverine alluvium. They are found on river terraces and are of minor occurences. The soil profile generally has a friable consistence throughout and are well to moderately well drained.

6.4 Gley Soils

The Gley soils have grey colours throughout the profile or with more than 50 percent gleying (gley mottles with chroma <2) within 50cm from the soil surface. This is due to the reduced condition caused by poor drainage. The Embang (Emb) Series soils identified are not of importance as they are found on an isolated spot.

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7. Soil Suitability

The soils suitability rating used in this report is based on the suitability classes for agricultural crops defined by Maas et ai, (1986). The suitabilty classes are rated from 1 to 5 based on the increasing severity and number of limitation affecting crop production. The suitability classes is shown in the table below.

Table 1: Number and Severity of Limitation For Every Suitability Classes

Number and Severity of Limitation Classes Minor Moderate Serious Very Serious

1 0-1 0 0 0 1 or its

2 2-3 equivalent 0 0 2 - 3 or its 1 or its

3 >4 equiv. equivalent 2-3 or its

4 - 4 equiv. 0

5 - - >4 ~ 1

Class 1 to 3 decline from suitable to moderately limiting in their agricultural capabilities and the range of crops that can be grown successfully. Class 4 is marginal for agriculture and suited to only a few specifically adapted crops. Class 5 is for soils and terrain which have little or no value for agriculture in their present condition. Seven limitation to crop production that have been recognised specific to mineral soils. and are shown in Table 2.

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·' Table 2: Limitation to Crop Suitability on Mineral Soils

Severity of Limitation Symbol Type of Limitation None Minor Moderate Serious Very Serious

a Depth to sulphidic layer > 100 75 - 100 50 - 75 < 50 -(cm)

c Depth to massive clay > 75 50 - 75 25 - 50 < 25 -(cm)

d Soil depth to impervious > 100 75 - 100 50 - 75 25 - 50 < 25 layer or 50% rock fragments (cm)

e Erosion hazard none low medium high very high f • Fertility medium - low fertility, low acute deficiency, -

retention very low retention i Inundation hazard none infrequent, short frequent, short infrequent, long frequent, long or

(frequency and duration submerged m Moisture-holding capacity high (loam to - medium (sandy low (fine and very low (coarse

oc clay) loam) medium sands) sand) 0 Depth of organic layer < 20 - 20 - 50 - -

(cm) r Stoniness (% rock < 0.1 0.1 - 3 3 - 15 15 - 20 > 50

fragments or stones within top 25cml

s Salinity of groundwater < 1,000 - - 1,00 - 4,000 > 4,000 umhos/cm)

t slope in degree 0-6 6 - 12 2 - 25 25 - 33 > 33 w Wetness (drainage class) well moderately well imperfectly poorly to very -

poorly

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8.0 Suitability Classes for Landuse Option in Forestry Application

In this report the aforementioned above suitability classes which were meant for agricultural crops were modified to suit for landuse options in reforestation work whereby the viable production of commercial timber on shifting agriculture and logged over forest areas is addressed. The landuse options is an integrated system comprising of 3 timber production management systems, i.e. Tree Plantation! Monoculture, EnrichmenU Line planting and Natural regeneration. Three suitability classes have been formulated by regrouping the first three classes as Class I and subsequent classes as Class II and Class Ill. Each of the three suitability classes is assigned land use options as shown in the Table 3.

Table 3 : Suitability Classes for Land use Option in Forestry Application

Suitability CLasses Suitability Classes Land use Option For Forestry For Forestry For Agricultural Crops

I 1,2 and 3 • Tree Plantation! Monoculture • EnrichmenU Line planting • Natural regeneration

11 4 • EnrichmenU Line planting

• Natural regeneration

III 5 • Natural regeneration only

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9.0 Landuse in Forestry Application

9.1 Tree Plantation/ Monoculture

The conventional tree plantation establishment involved eradication of all existing vegetation for the purpose of cultivating the desired tree species in a monoculture system to avoid any form of competition for plant nutrients and sunlight. The eradication of existing vegetation plant can be in the form of the traditional slashed and burnt, mechanical pushing by bulldozer or chemical poisoning method. This activity exposed the soil at the initial stage to soil erosion before organic matter and surface litter build up can begin. Thus the terrain must have stable slopes i.e. < 25 so as to prevent worst forms of erosion such as land slides. Gentler gradient will also ensure easier establishment and maintenance activities. Since the tree plantation is an intensive and high density planting system it requires good deep soils.

Fertiliser input is required at least between the period after planting and when the tree canopies have touched each others. Planting of leguminous cover crops can also be considered to reduce soil erosion and also to enrich the soil especially with nitrogen.

9.2 Enrichment! Line planting

This system is much less intensive as compared to the above system. Trees are planted along lines that are cleared. Existing vegetation is removed just adequately to enable sunlight penetration. The soil is thus lightly disturbed and naturally more stable. Existing supply of plant litters and decomposed organic matter enable the soil to provide nutrients for the planted trees. However, the terrain must be of gradient < 25 0 for shallow soils and < 33 0 for deeper soils.

9.3 Natural Regeneration

This landuse option is recommended for soils with terrain > 33 0 which is the lower limit for potential mass wasting to occur. Any disturbance to the soil such as the removal of vegetation may cause soil erosion to happen. Beside this imminent danger, human activities on such terrain will be hindered by footing problem. Shallow soils on terrain with slopes> 25 0 are also recommended for this land use option as trees on shallow soil may topple due to restricted anchorage. Soils with poor dcainage are also included under this option.

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10. Correlation of Soil and Terrain and the Land Use Options

Generally indigenous timber tree species like any other agricultural tree crops requires > 50cm soil depth, sandy loam to clay soil texture, well to imperfectly drainage, > 75cm depth to sulphidic layer, < 1,000 umhos!cm salinity of groundwater for satisfactory growth on mineral soils. Being a tree crop they are able to tolerate condition of frequent but short flooding. Table 4 shows several forest plantation species, exotic and indigenous and their tolerances to possible soil and site limitation (Butt and Sia, 1982). These level of tolerance are broad indicator and only estimates. Shorea macrophylla is shown having a high tolerance of flooding and water logging based on its natural habitat as of the riparian forest.

The Red Yellow Podzolic soils are generally suitable for CUltivation if the topography of land permits. The main limitations are steep topography and erosion hazard. Slopes in excess of 25 degrees required conservation measure for their utilization such construction of terraces for oil palm and rubber. The Nyalau soils have lower moisture-holding and nutrient retention capacities than Merit, Jakar and Bekenu soils and are thus generally considered slightly inferior.

The Skeletal soils of Meluan, Kapit and Tutoh Series are co~sidered not suitable agriculturally because of their shallow soil depth. Steep topography and serious erosion hazard are addition their limitations.

The general guides for the correlation of soil and terrain and the land use options that have been used in this report are shown in Table 5.

Table 5 : Correlation of Soil and Terrain and the Land Use Options

Soils and Terrain Land use Options

Alluvial soil on river levee • Tree Plantation! Monoculture Red Yellow Podzolic soils on terraces • EnrichmenU Line planting Red Yellow Podzolic soils, and associated • Natural regeneration with minor Skeletal soils on slopes < 25 0

Red Yellow Podzolic soils on slopes 25-33 0 • EnrichmenU Line planting Skeletal soils on slopes < 25 0 • Natural regeneration

Soils on slopes> 33 0

• Natural regeneration only Skeletal soils on slopes> 25 0

Gley soils •

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Table 4 : Summary of Site Tolerances

Tolerance of Tolerance of Tolerance of Tolerance of Tolerance of Species Flooding! Water Shallow Soil Infertility Acidic Soil Compaction

logging Acacia mangium Moderate-high High High Moderate-high Moderate-high

(seasonal) A/bizia fa/cataria Moderate MOderate-high High MOderate-high Moderate-high Araucaria Low-moderate Moderate Low-moderate Low-moderate Low cunninghamii A. hunstei"ii Moderate Moderate Moderate Low-moderate Low Ceiba pentandra Low Low-moderate Moderate-high Moderate Low-moder:ate Gme/ina arborea Low Low-moderate Low-moderate Moderate Low-moderate Ourio zibethinus Low-moderate Low Moderate-high Moderate-high Moderate Pinus caribaea Low-moderate (short, Low-moderate Moderate-high Moderate Low-moderate

occasional) Shorea High Low Moderate-high High Low macrophylla S. pinanga Low Moderate Moderate-high High Moderate S. splendida High Low M od erate-h igh High Low Sweetenia Low-moderate Moderate Moderate-high Low-moderate Moderate macrophylla

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11. Conclusion

This soils of the Sungai Muput Kiba Area, Anap Forest Reserve comprise predominantly of the Red Yellow Podzolic and Skeletal soil groups. The shallow and deep soils are found on both steep and gentle slopes. The estimated area under each suitability classes is approximately

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(i) 63 hectares of Class I, (ii) 57 hectare of Class 11 and (iii) 37 hectares of Class Ill.

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12. References

Butt, G. and Sia, P.C. (1982), Guide To Site Species Matching In Sarawak, 1. Selected Exotic and Native Plantation Species. Forest Research Report S.S. 1, Forest Department Sarawak.

Geological Survey Malaysia (1992), Geological Map of Sarawak, 2nd Edition.

Loi, K.S., Lah, J. Uyo, Eilers, R.G. and Louie, R.H. (1985), Terrain Classification In Sarawak. Malaysian Journal Of Tropical Geography, Volume 11, June 1985, Dept. of Geography, UM, Kuala Lumpur.

Maas, E.F, Tie, Y.L. and Lirn, C.P. (1979), Sarawak Land Capability Classification and Evaluation For Agricultural Crops. Technical Paper No. 5, Soil Division, Research Branch, Dept. of Agriculture Sarawak.

Teng, L.S. (1993), Keys to Soil Classification in Sarawak, Technical Paper No. 10, Soils Division Research Branch, Dept. Of Agriculture Sarawak.

Tie, Y.L. (1982), Soil Classification in Sarawak. Technical Paper No. 6, Soils Division Research Branch, Dept. of Agriculture Sarawak .

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Appendix

Profile 1

Soil Group: Red Yellow Podzolic Soils Family: Merit Series: Merit

Profile 2

Soil Group: Red Yellow Podzolic Soils Family: Merit Series: Merit

Profile 3

Soil Group: Red Yellow Podzolic Soils Family: Bekenu Series: Bekenu

Profile 4

Soil Group: Red Yellow Podzolic Soils Family: Bekenu Series: Bekenu

Profile 5

Soil Group: Skeletal Soils Family: Kapit Series: Kapit

Profile 6

Soil Group: Skeletal Soils Family: Kapit Series: Kapit

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Profile 1

Soil Group: Red Yellow Podzolic Soils Family: Merit Series: Merit Phase: Moderately deep Location: Line 17 Station 6 Drainage: Well drained Vegetation: Termuda (1 year fallow)

Depth (cm)1 Horizon

0-10 A

10- 17 Bt1

17 - 96 Bt2

96+ C

Description

Yellow (10 YR 7/6) Silty clay loam; friable, moderately strong subangular blocky structure, few fine and medium roots, few fine and medium pores, many moderately hard gravel and stones, gradual wavy boundary .

Yellow (10 YR 7/8) Silty clay loam; firm, strong medium subangular blocky structure, few fine and medium roots, few fine pores, few moderately hard gravel and stones, diffuse wavy boundary.

Yellow (10 YR 7/8) Silty clay; very firm, strong medium subangular blocky structure, few fine roots, few fine pores, many hard gravel and stones, clear irregular boundary.

Hard Shale

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Profile 2

Soil Group: Red Yellow Podzolic Soils Family: Merit Series: Merit Phase: Moderately deep Location: Line 13 Station 9 Drainage: Well drained Vegetation: Logged Primary Forest

Depth (cm)! Horizon

0-20 A

20 - 40 Bt1

40 - 66 Bt2

66+ C

Description

Brownish yellow (10 YR 6/6) Silty loam; friable, weak fine and medium subangular blocky structure, many fine and medium roots, many fine pores, gradual wavy boundary.

Brownish yellow (10 YR 6/8) Fine sandy clay loam; friable, moderately strong fine and medium subangular blocky structure, few fine and medium roots, few fine and medium pores, , diffuse and wavy boundary.

Brownish yellow (10 YR 6/8) Sandy clay; very firm, moderately strong fine and medium subangular blocky structure, few medium roots, few fine pores, few soft gravel and stones, clear wavy boundary.

Moderately Hard Shale

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Profile 3

Soil Group: Red Yellow Podzolic Soils Family: Bekenu Series : Bekenu Phase: Moderately deep Location: Line 8 Station 1 Drainage: Well drained Vegetation: Termuda (3 years fallow)

Depth (cm)1 Horizon

0-15 A

15 - 46 Bt1

46 - 98 Bh

98+ C

Description

Brownish yellow (10 YR 6/6) Fine sandy loam; very friable, moderately strong medium and coarse subangular blocky structure, few soft gravel, few medium and many fine roots, many fine and few medium pores and gradual wavy boundary.

Yellow (10 YR 7/6) Fine sandy clay loam; friable, moderately strong medium and coarse subangular blocky structure, few fine and medium roots, many fine and few medium pores and diffuse wavy boundary.

Yellow (10 YR 7/6) Clay loam; firm, moderately strong fine subangular blocky structure, few medium roots, few fine pores, abundance soft gravel and stones, (clear wavy boundary).

Very Soft Shale

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Profile 4

Soil Group: Red Yellow Podzolic Soils Family: Bekenu Series: Bekenu Phase: Moderately shallow Location: Line 2 Station 6 Drainage: Well drained Vegetation: Logged Primary Forest

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Depth (cm)1 Horizon

0-12 A

12 - 51 B

51+ C

Description

Very pale brown (10 YR 7/4) Silty loam; friable, moderately strong coarse subangular blocky structure, many medium and few fine roots, many fine and few medium pores and clear irregular boundary.

Yellow (10 YR 7/6) Silty clay loam; friable, moderately strong medium subangular blocky structure, few medium and many fine roots, many fine and few medium pores and clear irregular boundary.

Soft Shale

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Profile 5

Soil Group: Skeletal Soils Family: Kapit Series: Kapit Location: Line 13 Station 5 Drainage: Well drained Vegetation: Logged Primary Forest

Depth (cm)1 Horizon

0-5 A

5 -15 B

15+ C

Description

Brownish yellow (10 YR 6/8) Clay loam; firm, moderately strong fine subangular blocky structure, few hard gravel and stones, few medium and fine roots, few fine and many medium pores and gradual wavy boundary.

Yellow (10 YR 7/8) Clay loam; firm, strong fine and medium subangular blocky structure, many hard gravel and stones, few fine and medium roots, many fine pores and clear irregular boundary.

Soft Shale

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Profile 6

Soil Group: Skeletal Soils Family: Kapit Series : Kapit Location: Line 6 Station 2 Drainage: Well drained Vegetation: Termuda (3 years fallow)

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Depth (cm)1 Horizon

0-12 A

12 - 46 B

46+ C

Description .

Brownish yellow (10 YR 6/6) Silty loam;( ), strong fine and medium subangular blocky structure, few medium and many fine roots, few fine pores and clear wavy boundary.

Yellow (10 YR 7/8) Fine sandy clay loam; friable, strong fine and medium subangular blocky structure, few soft gravel and stones, few fine and medium roots, few fine pores and clear irregular boundary.

Soft Shale

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