I. INTRODUCTION
1.1. GENERAL INTRODUCTION
This soil survey and assessment report describes the results of a field survey and soil assessment of MOUILA LOT 3, MOUILA LOT 3 EXTENSION & NDENDE ESTATES located in the Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon, Africa. These Estates has been mainly planted with oil palm and belongs to OLAM PALM GABON S. A. This soil survey and soil assessment was carried out in October 2018 by PARAM AGRICULTURAL SOIL SURVEYS (M) SDN. BHD. at the invitation of Olam Palm Gabon S. A.
Essentially, the study objectives are:-
• to carry out a semi-detailed soil survey of the planted areas in the Estates totaling 25,803.0 ha at an intensity of one auger examination per 20 ha using free traversing.
• based on the above soil survey to produce a soil map at a scale of 1:25,000 showing phases of the soils found in the Estate.
• to produce a soil report describing the soils found in the area and to highlight the limitations present for oil palm cultivation.
• to propose amelioration methods to help overcome any problems encountered in the area.
• to group the soils into soil management groups.
• This data will assist the Estates to be certified under the Roundtable on Sustainable Palm Oil (RSPO) or other similar certification schemes.
1.2. LOCATION AND EXTENT
Mouila Lot 3 (Estates 10, 11, 12, 13 and 14), Mouila Lot 3 Extension (Estate 15) &
Ndende (Estates 16, 17 and 18) Estates consists of land situated mainly to the west of the Lambarene - Mouila - Ndende national road in Ngounie Province, Republic of
by other oil palm estates to the north and south (Figures 1.1, 1.2, 1.3, 1.4, 1.5, 1.6 and 1.7). The total planted area of the Estate is about 25,803.0 ha and has been planted with oil palm. The Lambarene - Mouila - Ndende national road connects to the various Estates through several adjoining earth roads in the north and on the eastern boundary.
Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates which belong to Olam Palm Gabon S. A., in Ngounie Province, Republic of Gabon consists of three contiguous parcels and is situated between latitudes 01° 52’ S and 02° 34’ S and longitudes 10° 54’
E and 11° 22’ E.
1.3. ACCESS
Access into the study area is by road. The all-weather metalled road, Lambarene - Mouila - Ndende national road which passes parallel to the eastern boundary of Estate 10 to 14 and cuts through Estate 15. From this metalled national road and various very short metalled roads extending from this national road which leads to various joining earth roads into all parts of the Estates. Within the Estates a good network of earth roads exists in the planted areas.
Figure 1.1. Location of the Republic of Gabon in Africa.
Figure 1.2. Location of the Olam Palm Gabon S. A.’s Estates in Republic of Gabon.
Figure 1.4. Location Map of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates in Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon.
Figure 1.5. Accessibility Map of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates in
Figure 1.6. Layout Plan of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates in Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon.
Figure 1.7. Satellite Imagery of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates in
II. THE ENVIRONMENT
2.1. TOPOGRAPHY AND DRAINAGE
The study area consists of level (0-4% slopes), undulating (4-12% slopes), and rolling land (12-24% slopes). Based on the study of the topographic maps followed by the field surveys, a terrain analysis of the area has been carried out (Figure 2.1 and Table 2.1).
The elevation in the area ranges from around 100 meters (300 feet) to over 200 meters (600 feet). The slope classes used in Malaysia are given in Table 2.1 and these have been used to map phases of the soil series during the survey.
2.2. GEOLOGY AND GEOMORPHOLOGY
The geology of the study area has been mapped by staff of the National Institute of Geology, 1981, and only three (3) types of parent materials (Dolomite/Limestone, Dolomite and Claystone/Sandstone) occur in the study area. The geological map of the area is given in Figure 2.2 (extracted from Geological Map of Gabon). However, based on the present survey it appears that the Dolomite/Limestone are overlain by Pediments.
Based on the present survey the parent materials are:
• Sub-Recent Alluvium
• Reworked Petroplinthite Pediments (P, P3 and P2)
• Sedimentary rocks (Sandstone/Shale)
Table 2.1. Slope classes used in Malaysia.
Slope Class
Description Map Symbol
Extent in Estate
(%) (°) Ha %
0–4 0–2 Level 1 551.1 2.1
4–12 2–6 Undulating 2 23,888.5 92.6
12–24 6–12 Rolling 3 1,363.4 5.3
24–38 12–20 Hilly 4 - -
38–50 20–25 Somewhat steep 5 - -
>50 >25 Steep 6 - -
Total: 25,803.0 100.0
Figure 2.1. Contour Map of Mouila Lot 3, Mouila
Lot 3 Extension & Ndende Estates in Mougalaba, Douya Onoye & Dola Departments,
Ngounie Province, Republic of Gabon.
Figure 2.2. Geological Map of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates, Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon.
(Source: Geological Map of Gabon, National Institute of Geology, France, 1981, Scale 1:2,000,000)
2.3. CLIMATE
Climatological and hydrological studies are aimed at determining the intensity and distribution of precipitation and other related phenomena with respect to place and time.
The information thus obtained, coupled with information on soils, terrain etc. is required to determine what crops can be grown in the various locations and helps determine the management practice to be carried out.
The rainfall and raindays data for Mouila Lot 3, MOUTASSOU -Station 1, Estate 12 and NDENDE -Fera Station, Estate 18 for the period 2016-2018 (2019-incomplete year) is also given in Tables 2.2 and 2.3 respectively.
2.3.1. Rainfall and Raindays
The rainfall and raindays data for MOUTASSOU -Station 1, Estate 12 for the three- year period 2016-2018 (2019-incomplete year) is given in Table 2.3. This data shows that the total annual rainfall for the period ranges from 1,253 mm to 1,515 mm. About four dry months (<100 mm) commonly occur in the months of June, July, August and September but this varies from year to year. The total annual raindays ranges from 170 to 183. The three-year means for MOUTASSOU -Station 1, Estate 12 are 1,455 mm and 182 days.
The rainfall and raindays data for NDENDE -Fera Station, Estate 18 for the three-year period 2016-2018 (2019-incomplete year) is given in Table 2.3. This data shows that the total annual rainfall for the period ranges from 1,348 mm to 1,650 mm. About four dry months (<100 mm) commonly occur in the months of June, July, August and September but this varies from year to year. The total annual raindays ranges from 124 to 174. The three-year means for NDENDE -Fera Station, Estate 18 are 1,501 mm and 156 days.
Table 2.2. Total monthly rainfall (mm) and raindays for Mouila Lot 3 Estate, MOUTASSOU -Station 1, Estate 12 (2016-2018).
Year Month
2016 2017 2018 2019 3-Year Mean
(2016-2018)
mm days mm days mm days mm days mm days
Jan 160 15 217 19 209 19 262 25 212 20
Feb 249 16 177 19 157 22 175 19 189 19
Mar 199 22 102 17 187 19 163 21 163 20
Apr 195 22 84 14 132 14 279 21 173 18
May 91 7 143 15 128 16 - - 121 13
Jun 0 0 1 5 16 3 - - 6 3
Jul 3 5 5 6 0 0 - - 3 4
Aug 37 7 2 5 6 7 - - 15 6
Sept 9 9 35 13 13 9 - - 19 10
Oct 146 22 253 24 243 24 - - 214 23
Nov 52 29 282 24 187 27 - - 173 27
Dec 113 16 214 18 173 23 - - 167 19
Total: 1,253 170 1,515 179 1,452 183 879 86 1,455 182 Dry month (<100 mm)
Table 2.3. Total monthly rainfall (mm) and raindays for Ndende Estate, NDENDE -Fera Station, Estate 18 (2016-2018).
Year Month
2016 2017 2018 2019 3-Year Mean
(2016-2018)
mm days mm days mm days mm days mm days
Jan 19 7 203 18 229 15 158 27 152 17
Feb 177 14 115 18 95 12 178 16 141 15
Mar 305 20 169 21 140 18 196 22 203 20
Apr 243 16 269 20 162 18 249 17 231 18
May 110 7 162 13 148 18 - - 140 13
Jun 0 0 7 5 1 3 - - 3 3
Jul 3 5 1 1 2 6 - - 2 4
Aug 14 1 3 2 1 1 - - 6 1
Sept 4 1 21 12 6 6 - - 10 6
Oct 110 11 231 23 170 24 - - 170 19
Nov 243 23 245 23 314 22 - - 267 23
Dec 120 19 225 18 184 15 - - 176 17
Total: 1,348 124 1,650 174 1,451 158 781 82 1,501 156 Dry month (<100 mm)
III. SOILS OF THE STUDY AREA
3.1. SOIL SURVEY METHODOLOGY
The initial approach to the soil survey was to study the existing information available for the area. In the Reconnaissance Soil Map of Gabon, Sheets Fougamaou & Ndende (M. Delhumeau & J. Collinet, 1974) a reconnaissance soil map of has been published at a scale of 1:200,000. On this map Mouila Lot 3 Extension & Ndende Estates has been mapped as belonging to fourteen (14) soil associations (Figure 3.1 and Legend).
Since the study area had a road map of the Estate showing the roads block boundaries (Figure 3.2) in the Estate, this map was enlarged to a scale of 1:25,000 and used for the field survey. As required in the Terms of Reference, an intensity of one auger examination point for every twenty hectares was maintained and a system of free traversing was used for the survey.
At each examination point the soil was examined using a Jerret soil auger and the soils examined to a depth of 105 cm (40 inches) or to an impenetrable layer. At each observation point, the depth, the colour, mottling, texture, consistence, presence of rock fragments and roots were described using the terminology of the FAO’s Guidelines for Soil Description (FAO, 1977) and the Malaysian Standards Terminology for Soil Description (Paramananthan, 1997). Other characteristics such as the slope, drainage class, depth of peat (if any), water-table were also described.
The data collected during the field survey were plotted on the 1:25,000 scale road map of the Estate and the final soil map produced at this scale. In compiling the map, the geologic, topographic and other features were used in extrapolating the soil boundaries between the examination points. The distribution of the soils is shown on the soil map (Figure 3.3). The soil series names in Malaysia (Paramananthan, 2010, Revised 2014) were used as map symbols and on the legend. Slope phases of the soil series were also used.
Figure 3.1. Reconnaissance Soil Map of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates in Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon. (Source: Reconnaissance Soil Map of Gabon, Sheets Fougamaou & Ndende, M.
Delhumeau & J. Collinet, 1974, Scientific Research Department, France, Scale 1:200,000)
RECONNAISSANCE SOIL MAP LEGEND
MOUILA LOT 3, MOUILA LOT 3 EXTENSION AND NDENDE ESTATES OLAM PALM GABON S.A.
Mougalaba, Douya Onoye & Dola Departments Ngounie Province
Republic of Gabon
Map
Symbol Soil Group Sub-Group Parent Material
2 Soil with little profile
development (Regosols) Erosional soil Colluvium over shales/limestone
6
Ferralitic soils, highly desaturated, typically
indurated with concretions.
- Calcareous – Schist.
Nyanga Formation
13 Ferralitic soils Strongly desaturated
indurated
Colluvium from schists/Gneiss of Nyanga Formation
17
Hydromorphic soils, Organic deposits, oligotrophic
peat, low fertility.
Oligotropic, deep organic soils
Organic deposits/
Riverine alluvium
20
Hydromorphic soils, Moderately deep organic soils
and humic gleys.
- Recent Alluvium
21 Hydromorphic soils,
gley soils. - Recent Alluvium
23 Pseudo gley soils - Recent Alluvium
24 Pediments
(Lateritic soils)
Plains over karst limestone of N’dende
Formation
Colluvium over limestone
25 Pediments
(Lateritic soils)
Undulating plains over sedimentary rocks
Colluvium over sedimentary rocks
26 Pediments with plains (Lateritic)
Humic podzols and argillic
horizons Colluvium with sandy textures
27 Pediments with plains (Lateritic)
Undulating plains over with low hills (lateritic)
Colluvial plains with sandy clay textures
28 Pediments with plains (Lateritic)
Undulating plains with low hills
Colluvium plains with sand to sandy loam textures
29a Hydromorphic soils (Wet) Depressions with
waterlogged soils Textures sand clay
30 Hydromorphic soils (Wet) Plains with poorly drained soils
Colluvium with sand to sandy clay textures
Figure 3.2a. Road and Block Map of Mouila Lot 3 and Mouila Lot 3 Extension Estates in Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon.
Figure 3.2b. Road and Block Map of Ndende Estate in Dola Department, Ngounie Province,
Figure 3.3a. Semi-detailed Soil Map of Mouila Lot 3 Estate in Mougalaba, Douya Onoye &
Dola Departments, Ngounie Province, Republic of Gabon.
Figure 3.3c. Semi-detailed Soil Map of Ndende Estate in Dola Department, Ngounie Province, Republic of Gabon.
Table 3.1. Characteristics of the soil map units of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Parent Material
Map Symbol
Soil Series
Slope
Class (%) Description
Mouila Lot 3 Estate
Mouila Lot 3 Estate Extension
Ndende Estate Total Extent
Ha % Ha % Ha % Ha %
Sedimentary rocks
Mlu/3 Malau Rolling
(12-24)
Deep (>100 cm) brownish yellow sandy loam. Weak to moderate medium subangular blocky; friable. Patchy clayskins (argillic). Well drained. Soils developed over sedimentary rocks.
15.1 0.1 - - - - 15.1 0.1
Kra/3 Kekura Rolling (12-24)
Shallow (<50 cm) yellow, fine sandy clay loam. Well drained. Weak medium and fine subangular blocky;
friable. Weathered sandstone fragments occur within 50 cm depth. Soils over sandstones.
- - 4.3 0.1 - - 4.3 -
Pediments-Reworked Petroplinthite -P
Mca/3
Malacca
Rolling (12-24)
Shallow (<50 cm) gravelly to stony clay. Yellowish red to red; weak medium subangular blocky; friable. Patchy clayskins (kandic). Stones consist of subangular petroplinthite gravels. Well drained. Soils developed over pediments (P) surface.
- - - - 15.1 0.2 15.1 0.1
Mca/2 Undulating
(4-12) - - - - 7.5 0.1 7.5 0.1
Gmi/3 Gajah Mati
Rolling (12-24)
Shallow (<50 cm) gravelly clay. Yellowish brown to strong brown; weak medium subangular blocky; friable.
Patchy clayskins. Stones consist of subangular petroplinthite gravels. Well drained. Soils developed over pediments (P) surface.
- - - - 22.6 0.3 22.6 0.1
Pediments-Reworked Petroplinthite -P3 Trp/3
Terap
Rolling (12-24)
Moderately deep (50-100 cm) yellowish brown to strong brown. Fine sandy clay to 70 cm over stony clay.
Moderate medium subangular blocky; friable. Patchy clayskins. Stones consist of subrounded petroplinthite (lateritic) gravels. Well drained. Soils over Pediments (P3).
- - - - 15.0 0.2 15.0 0.1
Trp/2 Undulating
(4-12) - - - - 22.7 0.3 22.7 0.1
Pdu/3
Pedu
Rolling (12-24)
Shallow (<50 cm) gravelly loam. Strong brown to brownish yellow; weak medium subangular blocky structures; friable. Patchy clayskins. Stones consist of subrounded petroplinthite gravels. Well drained. Soils developed over pediments (P3) surface.
102.3 0.7 - - 775.7 10.3 878.0 3.4
Pdu/2 Undulating
(4-12) 652.5 4.5 300.8 7.5 1,634.2 21.7 2,587.5 10.0
Pdu/fsl/3 Pedu/
fine sandy
loam
Rolling (12-24)
Shallow (<50 cm) gravelly fine sandy loam. Strong brown to brownish yellow; weak medium subangular blocky structures; friable. Patchy clayskins. Stones consist of subrounded petroplinthite gravels. Well drained. Soils developed over pediments (P3) surface.
- - 35.4 0.9 - - 35.4 0.1
Pdu/fsl/2 Undulating
(4-12) 2,668.2 18.4 76.0 1.9 - - 2,744.2 10.6
Parent Material
Map Symbol
Soil Series
Slope
Class (%) Description
Mouila Lot 3 Estate
Mouila Lot 3 Estate Extension
Ndende Estate Total Extent
Ha % Ha % Ha % Ha %
Pediments-Reworked Petroplinthite -P3 Nrg/3
Nerang
Rolling
(12-24) Moderately deep (50-100 cm) brownish yellow to strong brown fine sandy loam to over 50 cm overlying a dense thick (>25 cm) gravelly clay. Gravels consist of rounded and subrounded petroplinthic gravels. Weak medium to fine structure; friable; patchy clayskins. Within 100 cm soil is variegated. Moderately well drained soil on Pediment (P3) surfaces.
101.3 0.7 - - 165.6 2.2 266.9 1.0
Nrg/2 Undulating
(4-12) - - 874.2 21.8 2,838.6 37.7 3,712.8 14.4
Nrg/1 Level
(0-4) - - - - 22.6 0.3 22.6 0.1
Nrg/fsl/3
Nerang/
fine sandy
loam
Rolling (12-24)
Moderately deep (50-100 cm) brownish yellow to strong brown fine sandy loam to over 50 cm overlying a dense thick (>25 cm) gravelly clay. Gravels consist of rounded and subrounded petroplinthic gravels. Weak medium to fine structure; friable; patchy clayskins. Within 100 cm soil is variegated. Moderately well drained soil on Pediment (P3) surfaces.
- - 111.0 2.8 - - 111.0 0.4
Nrg/fsl/2 Undulating
(4-12) 5,797.9 40.0 630.1 15.7 - - 6,428.0 24.9
Pediments- Reworked Petroplinthite -P2
Dpr/2 Dampar Undulating (4-12)
Moderately deep (50-100 cm) brownish yellow to strong brown fine sandy clay loam to over 50 cm overlying a dense thick (>25 cm) gravelly clay. Gravels consist of rounded and subrounded petroplinthic gravels. Weak medium to fine structure; friable; patchy clayskins. Within 100 cm soil is variegated. Moderately well drained soil on Pediment (P2) surfaces.
- - - - 30.1 0.4 30.1 0.1
Sub-Recent Alluvium
Tbk/2 Tebok Undulating (4-12)
Deep (>100 cm) yellowish brown fine sandy clay.
Moderate medium subangular blocky; friable to firm.
Patchy clayskins (kandic). Well drained. Soils developed over Sub-Recent Alluvium.
- - 53.1 1.3 15.1 0.2 68.2 0.3
Rsu/2 Rasau Undulating (4-12)
Deep (>100 cm) yellowish brown fine sandy clay loam.
Moderate medium subangular blocky; friable. Patchy clayskins (kandic). Well drained. Soils developed over Sub-Recent Alluvium.
87.0 0.6 2.8 0.1 67.8 0.9 157.6 0.6
Nka/2
Nangka
Undulating
(4-12) Deep (>100 cm) yellow to pale yellow fine sandy loam.
Weak medium and fine subangular blocky; very friable.
No clayskins (cambic). Well to moderately well drained.
Soils developed over Sub-Recent Alluvium.
1,740.9 13.6 95.8 2.4 1,039.9 13.8 2,876.6 11.1
Nka/1 Level
(0-4) - - - - 135.6 1.8 135.6 0.5
Table 3.1. Characteristics of the soil map units of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Parent Material
Map Symbol
Soil Series
Slope
Class (%) Description
Mouila Lot 3 Estate
Mouila Lot 3 Estate Extension
Ndende Estate Total Extent
Ha % Ha % Ha % Ha %
Sub-Recent Alluvium
Sri/2
Serai
Undulating
(4-12) Deep (>100 cm) white sands. Albic horizon.
Structureless, loose. Excessively drained. Soils developed on Sub-Recent Alluvium.
- - 1,820.3 45.5 489.5 6.5 2,309.8 9.0
Sri/1 Level
(0-4) 159.5 1.1 - - 233.4 3.1 392.9 1.5
Bnr/fsl/2
Banar/
fine sandy
loam
Undulating (4-12)
Deep (>100 cm) pale yellow to 50 cm and light gray below 50 cm fine sandy loam. Weak coarse subangular blocky;
friable. No clayskins (cambic horizon). Imperfectly drained. Soils developed over Sub-Recent Alluvium.
507.7 3.5 - - - - 507.7 2.0
Bso/2 Buso Undulating (4-12)
Shallow (<50 cm) dark brown to white sand overlying thick (>10 cm) strongly cemented hard pan (spodic) layer within 50 cm depth. Imperfectly drained. Seasonally flooded. Soils developed over Sub-Recent Terrace Alluvium.
2,435.8 16.8 - - - - 2,435.8 9.4
Total: 14,268.2 100.0 4,003.8 100.0 7,531.0 100.0 25,803.0 100.0
3.2. DESCRIPTION OF THE SOILS
The unit of mapping currently used in Malaysia is the ‘soil series’. A soil series is defined as a soil type having similar morphological features and formed on similar parent material. The soil series is identified based on the Soils of Malaysia (Paramananthan, 2000) the Keys to the Identification of Malaysian Soils According to Parent Materials (Paramananthan, 2010, updated 2014). These have been used in this survey to name the soil series. However as these soil series can still be broad when used in making suitability or management interpretations, a subdivision of the soil series into phases using soil depth, slope class, drainage class and subsoil colours where necessary was made during the survey to define the soil mapping units. A summary of the main properties of the different soils mapped in the area is given in Table 3.1. A total of twenty-five (25) soil mapping units were identified in the study area. These belong to sixteen (16) soil series as defined in Malaysia.
The parent materials found in the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates consist mainly of sedimentary rocks, soils over pediments and sub-recent riverine alluvium.
In mapping the soils in the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates a number of criteria can be used to separate the soils. Some of the criteria used include:
For Mineral Soils
• Presence of an oxic, kandic, argillic or cambic horizon.
• Soil depth — deep (> 100 cm), moderately deep (50–100 cm), shallow (< 50 cm).
• Texture in the subsoil (25–100 cm depth or shallower).
• Presence and depth of stones/gravels.
• Colour at 50 cm depth or above a lithic or paralithic contact in shallow soils.
• Cation exchange capacity and base saturation.
• Drainage class.
3.2.1. Soils Developed Over Sedimentary Rocks
Soils developed over metamorphic and sedimentary rocks occupy the northern part of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates. These rocks consist of sandstones and shales. These soils occur on rolling (12-24%) terrain. A total of two (2) soil mapping units consisting of two (2) soil series have been identified on these parent materials on the Estates. The key to the identification of these soils is summarised in Table 3.2.
Malau Series. Soils of the Malau Series are deep, well drained soils developed over sedimentary rocks. These soils are characterized by their yellowish brown to brownish yellow fine sandy loam subsoils to a depth of around 100 cm. These soils occur on rolling (12-24% or 6-12° slopes) terrain. Locally especially on hill tops a spodic horizon may develop over the sandstone (Bako Series/shallow). The spodic horizon often occurs within 50 cm depth. The topsoils of the Malau Series are a dark yellowish brown (10YR3/4) sandy loam to loamy sand with weak medium and fine subangular blocky structure and friable consistence. The subsoils are a deep yellowish brown (10YR5/6–5/8), brownish yellow (10YR6/6–6/8) to reddish yellow (7.5YR6/6–6/8) fine sandy loam with weak medium to coarse subangular blocky structure and friable consistence. Patchy clayskins occur on ped faces. Weathered sedimentary rocks occur at depths over 100 cm. Soils of the Malau Series occupy 15.1 ha or 0.1% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Kekura Series. Soils of the Kekura Series are shallow, well drained soils developed over mainly sandstone parent material. These soils have a fine sandy loam topsoil which grade to fine sandy clay loam with depth. Colours are brownish yellow to yellow.
The parent material is encountered within 50 cm depth. The surface soils of the Kekura Series is a brown (10YR5/3) fine sandy loam with weak fine subangular blocky structures and friable consistence. The subsoils are a brownish yellow (10YR6/6–6/8) to yellow (10YR7/6–7/8) fine sandy clay loam with weak medium to fine subangular blocky structures and friable consistence. Clayskins may or may not be present. The weathered sandstone parent material is encountered within 50 cm of the soil surface.
Soils of the Kekura Series occur on rolling (12-24% or 6-12° slopes) terrain and occupy 4.3 ha of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Table 3.2. Key to the Identification of soils over Sedimentary, Calcareous, Metamorphic Rocks and Tuffaceous Sedimentary Rocks.
3.2.2. Soils Developed Over Pediments (Reworked Lateritic Gravels)
Eight (8) soils, the shallow (<50 cm) Malacca, Gajah Mati, Pedu and Pedu/fine sandy loam Series and the moderately deep (50-100 cm) Terap, Nerang, Nerang/fine sandy loam and Dampar Series soils have been mapped. These soils are developed over reworked lateritic gravels or pediments (P and P3). The Key to their identification is given in Table 3.3.
Malacca Series. Soils of the Malacca Series occur on undulating (4-12% or 2-6°
slopes) and rolling (12-24% or 6-12° slopes) terrain. Soils of the Malacca Series are characterized by the presence of lateritic stones or gravels in a fine sandy clay matrix with the gravel layer having its upper boundary within 50 cm – sometimes at the surface.
Where the gravels form a dense layer close to the surface it can form an impediment to root penetration and also result in moisture stress. Additional phosphate fertilizers are necessary to encourage root growth. Soils of the Malacca Series are shallow, well drained soils with gravelly to stony clay textures and yellowish red to red colours.
Structures are weak medium subangular blocky and consistence is friable. Patchy clayskins occur on ped faces. These are lateritic soils which are developed over sandstones and shales and reworked lateritic gravels and stones (P surface). The subangular lateritic gravels form a dense layer within 50 cm of the soil surface and hence be a hindrance to root growth.
The topsoils of the Malacca Series consists of a light yellowish brown (10YR6/4) sandy loam to sandy clay loam. Structures are weak fine subangular blocky and consistence is friable. The subsoils to 100 cm depth consists of a yellowish red (5YR5/6-5/8) to red (2.5YR4/6) gravelly sandy clay with weak subangular blocky and friable consistence.
Patchy clayskins occur on ped faces. The gravels consist of a dense layer of subangular lateritic gravels and stones which are encountered within 50 cm depth. These soils occupy 22.6 ha or 0.1% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Gajah Mati Series. Soils of the Gajah Mati Series are shallow, well drained soils with gravelly clay textures and brownish yellow to strong brown colours. These are lateritic soils which are developed over sandstones and shales and reworked lateritic gravels. The topsoils of the Gajah Mati Series consists of a light yellowish brown (10YR6/4) sandy loam to sandy clay loam. Structures are weak fine subangular blocky
consistence. Patchy clayskins occur on ped faces. The gravels consist of a dense layer of sub-rounded lateritic gravels which are encountered within 50 cm depth. These soils have been mapped on rolling (12-24% or 6-12° slopes) terrain and occupy 22.6 ha or 0.1% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Terap Series. Soils of the Terap Series are moderately deep, well drained soils with sandy clay over gravelly clay textures and yellowish brown to strong brown colours.
These lateritic soils and are developed over reworked lateritic gravels (P3 surface). The sub-rounded lateritic gravels form a dense layer between 50 to 100 cm of the soil surface. These soils occur on undulating (4-12% or 2-6° slopes) and rolling (12-24%
or 6-12° slopes) terrain. The topsoils of the Terap Series consists of a light yellowish brown (10YR6/4) sandy loam to sandy clay loam. Structures are weak fine subangular blocky and consistence is friable. The subsoils to below 50 cm depth consists of a yellowish brown (10YR5/6-5/8) to strong brown (7.5YR5/6-5/8) sandy clay overlying a gravelly sandy clay with weak subangular blocky and friable consistence. Patchy clayskins occur on ped faces. The gravels consist of a dense layer of sub-rounded lateritic gravels which are encountered below 50 cm depth. These soils occupy 37.7 ha or 0.2% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Pedu Series. Soils of the Pedu Series are shallow (<50 cm), well drained soils with gravelly fine sandy clay loam textures and brownish yellow to strong brown colours.
Structures are weak medium subangular blocky and consistence is friable. Patchy clayskins occur on ped faces. These are lateritic soils which are developed over pediments or often called sol remanie and consist of reworked lateritic gravels. The sub-rounded lateritic gravels form a dense layer within 50 cm of the soil surface. The topsoils of the Pedu Series consists of a light yellowish brown (10YR6/4) sandy loam to sandy clay loam. Structures are weak fine subangular blocky and consistence is friable. The subsoils to 100 cm depth consists of a brownish yellow (10YR6/6-6/8) gravelly sandy clay loam to fine sandy loam with weak subangular blocky and friable consistence. Patchy clayskins occur on ped faces. The gravels consist of a dense layer of sub-rounded lateritic gravels which are encountered within 50 cm depth. These soils have been mapped on undulating (4-12% slopes) and rolling (12-24% slopes) terrain
and occupy 3,465.5 ha or 13.4% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Pedu Series/fine sandy loam. Soils of the Pedu/fine sandy loam Series are shallow (<50 cm), well drained soils with gravelly fine sandy loam textures and brownish yellow to strong brown colours. Structures are weak medium subangular blocky and consistence is friable. Patchy clayskins occur on ped faces. These are lateritic soils which are developed over pediments or often called sol remanie and consist of reworked lateritic gravels. The sub-rounded lateritic gravels form a dense layer within 50 cm of the soil surface. The topsoils of the Pedu/fine sandy loam Series consists of a light yellowish brown (10YR6/4) sandy loam to sandy clay loam. Structures are weak fine subangular blocky and consistence is friable. The subsoils to 100 cm depth consists of a brownish yellow (10YR6/6-6/8) gravelly sandy clay loam to fine sandy loam with weak subangular blocky and friable consistence. Patchy clayskins occur on ped faces.
The gravels consist of a dense layer of sub-rounded lateritic gravels which are encountered within 50 cm depth. These soils have been mapped on undulating (4-12%
slopes) and rolling (12-24% slopes) terrain and occupy 2,779.6 ha or 10.7% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Nerang Series. Soils of the Nerang Series are moderately deep (50-100 cm), well drained soils with fine sandy clay loam or fine sandy loam textures to over 50 cm overlying a moderately dense layer of sub-rounded lateritic gravels embedded in a fine sandy clay loam to fine sandy loam. Colours are brownish yellow to strong brown and structure weak medium and fine subangular blocky with friable consistence. Patchy clayskins occur on ped faces. These lateritic soils are developed over Pediments (P3) or Reworked petroplinthic (lateritic) gravels. These soils are well to moderately well drained. The topsoils of the Nerang Series are a pale brown (10YR6/3) fine sandy clay loam or fine sandy loam. The upper subsoils to around 60 cm consists of brownish yellow (10YR5/6-5/8) to strong brown (7.5YR5/6-5/8) fine sandy clay loam to fine sandy loam. Structures are weak fine subangular blocky and consistence is friable.
Patchy clayskins occur on ped faces. Soils of the Nerang Series occur on level to rolling (0-24% slopes) terrain and occupy 4,002.3 ha or 15.5% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Table 3.3. Key to the Identification of Skeletal Soils.
Nerang/fine sandy loam Series. Soils of the Nerang/fine sandy loam Series are moderately deep (50-100 cm), well drained soils with over 50 cm overlying a moderately dense layer of sub-rounded lateritic gravels embedded in a fine sandy clay loam to fine sandy loam. Colours are brownish yellow to strong brown and structure weak medium and fine subangular blocky with friable consistence. Patchy clayskins occur on ped faces. These lateritic soils are developed over Pediments (P3) or Reworked petroplinthic (lateritic) gravels. These soils are well to moderately well drained. The topsoils of the Nerang/fine sandy loam Series are a pale brown (10YR6/3) fine sandy clay loam or fine sandy loam. The upper subsoils to around 60 cm consists of brownish yellow (10YR5/6-5/8) to strong brown (7.5YR5/6-5/8) fine sandy clay loam to fine sandy loam. Structures are weak fine subangular blocky and consistence is friable. Patchy clayskins occur on ped faces. Soils of the Nerang/fine sandy loam Series occur on undulating to rolling (4-24% slopes) terrain and occupy 6,539.0 ha or 25.3% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Dampar Series. Soils of the Dampar Series are moderately deep (50-100 cm), well drained soils with fine sandy clay loam or fine sandy loam textures to over 50 cm overlying a moderately dense layer of sub-rounded lateritic gravels embedded in a fine sandy clay loam to over 50 cm overlying a dense thick (>25 cm) gravelly clay. Gravels consist of rounded and subrounded petroplinthic gravels. Colours are brownish yellow to strong brown and structure weak medium and fine subangular blocky with friable consistence. Patchy clayskins occur on ped faces. These soils are well to moderately well drained. The topsoils of the Dampar Series are a pale brown (10YR6/3) fine sandy clay loam or fine sandy loam. The upper subsoils to around 60 cm consists of brownish yellow (10YR5/6-5/8) to strong brown (7.5YR5/6-5/8) fine sandy clay loam to fine sandy loam. Structures are weak fine subangular blocky and consistence is friable.
Patchy clayskins occur on ped faces. Soils of the Dampar Series occur on undulating (4-12% slopes) terrain and occupy 30.1 ha or 0.1% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
3.2.3. Soils Developed Over Sub-Recent Alluvium
Soils developed over Sub-Recent Alluvium occur on level to undulating terrain in the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates. Six (6) soil series (Tebok,
texture. The Tebok, Rasau and Nangka Series are well drained while the Banar/fine sandy loam and Buso Series imperfectly drained and the Serai Series is excessively drained. The drainage classes used is shown in Figure 3.4 and the Key to the Identification in Table 3.4.
Tebok Series. Soils of the Tebok Series are deep, well drained soils developed over sub-recent alluvium. They are characterized by their brownish yellow fine sandy clay subsoils. These soils occur on undulating (4-12% or 2-6° slopes) terrain. The topsoils of the Tebok Series consist of a brown (10YR5/3) fine sandy clay loam to fine sandy clay. Structures are weak fine subangular blocky and consistence is friable. The subsoils to over 100 cm are a uniform brownish yellow (10YR6/6) fine sandy clay.
Structures are moderate medium subangular blocky and consistence is friable. Patchy clayskins occur on ped faces. Soils of the Tebok Series occupy 62.8 ha or 0.3% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Rasau Series. Soils of the Rasau Series are deep, well drained soils developed over sub-recent alluvium. They are characterized by their brownish yellow fine sandy clay loam subsoils. These soils occur on undulating (4-12% or 2-6° slopes) terrain. The topsoils of the Rasau Series consist of a brown (10YR5/3) fine sandy clay loam. The subsoils to over 100 cm are a uniform brownish yellow (10YR6/6) fine sandy clay loam.
Structures are weak to moderate medium subangular blocky and consistence is friable.
Patchy clayskins occur on ped faces. Soils of the Rasau Series occupy 157.6 ha or 0.6%
of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Nangka Series. Soils of the Nangka Series are developed over Sub-Recent Alluvium and occur on level (0-4% or 0-2° slopes) to undulating (4-12% or 2-6° slopes) terrain.
These soils are a deep (>100 cm) well drained soil with fine sandy loam textures and yellow colours. The topsoils of the Nangka Series consist of a brown (10YR5/3) fine sandy loam to loamy fine sand with weak fine subangular blocky structure and friable consistence. This grades into a deep uniform yellow (10YR7/6-7/8) fine sandy loam.
Structures are weak medium subangular blocky and consistence is friable. No clayskins occur in this soil. Soils of the Nangka Series occupy 3,012.2 ha or 11.6% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Figure 3.4. Diagramatic representation of drainage classes (after Paramananthan, 1987, updated 2010).
Serai Series. Soils of the Serai Series are deep (>100 cm) soils developed over sand on the sub-recent alluvium. These soils have a humus-rich sandy topsoil which then gives rise to a deep uniform light gray to white loose sand which has been bleached (albic horizon). A spodic horizon, if present, occurs below 100 cm depth. The soils are structureless and loose resulting in an excessively drained soil which is prone to moisture stress. These soils have been mapped on on level (0-4% or 0-2° slopes) to undulating (4-12% or 2-6° slopes) terrain. The topsoils of the Serai Series consists of a thin structureless brown (10YR5/3) sand. This grades into a deep light gray (10YR7/1) or white (10YR8/1) loose structureless sand (albic horizon) which extends to over 100 cm depth. Soils of the Serai Series occupy 2,7.2.7 ha or 10.5% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Banar Series/fine sandy loam Series. Soils of the Banar/fine sandy loam Series are developed over Sub-Recent Alluvium and occur on undulating (4-12% or 2-6° slopes) terrain. The Banar/fine sandy loam Series soils are a deep, imperfectly drained soils with brownish yellow to yellow upper subsoils and fine sandy loam textures. The topsoils of the Banar/fine sandy loam Series consist of a brown (10YR4/3) fine sandy loam with weak coarse subangular blocky structure and friable consistence. This grades to a yellow (10YR7/6) to brownish yellow (10YR6/6) fine sandy loam. Structures are weak medium subangular blocky and consistence friable. No clayskins may occur on ped faces. At depths below 50 cm the colour of the soil matrix changes to light gray (10YR7/2) and many medium yellow (10YR7/8) or brownish yellow (10YR6/6) mottles may occur. Structures become weaker and coarser with depth. Soils of the Banar/fine sandy loam Series occupy 507.7 ha or 2.0% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
Buso Series. Soils of the Buso Series are shallow (<50 cm) soils developed over sandy Sub-Recent Terrace Alluvium. The soil depth is controlled by the presence of a thick strongly cemented ‘coffee-rock’ or spodic horizon that impedes both root penetration and water movement in these soils. Thus these sandy soils are subject to flooding in the rainy season and moisture stress in the dry season. The presence of the shallow cemented horizon can also cause wind damage due to poor anchorage. Textures are uniformly sandy and the soil is structureless. These soils have been mapped on undulating (4-12% slopes) terrain. The topsoils of the Buso Series to about 30 cm is a
surface can have a thin layer of white (10YR8/1) sand. A thin layer of light gray (10YR7/2) to white (10YR8/1) sand which has been leached (albic horizon) may be present. Around 30 to 40 cm depth a very hard and compact dark brown (10YR3/3)
‘coffee-rock’ or cemented spodic horizon is encountered. This horizon can be more than 30 cm thick below which loose sand or a massive silty clay is encountered. Soils of the Buso Series occupy 2,435.8 ha or 9.4% of the Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates.
3.3. SOIL CLASSIFICATION
The classification of the soils mapped in the Plantation according to the Keys to Soil Taxonomy — Eleventh Edition (Soil Survey Staff, 2010), the FAO/UNESCO Soil Map of the World — Revised Legend (FAO, 1990), the Malaysian Soil Taxonomy — Revised Second Edition (Paramananthan, 2014) and the World Reference Base for Soil Resources (FAO, 2014) is given in Table 3.5.
Table 3.5. Classification of the soils.
Soil Series
Keys to Soil Taxonomy – Eleventh Edition (Soil Survey Staff,
2010)
FAO/UNESCO Soil Map of the World —
Revised Legend (FAO, 1990)
Malaysian Soil Taxonomy
— Second Edition (Paramananthan,
2011)
World Reference Base for Soil Resources 2014 World
Soil Resources Reports No. 106, FAO ROME (IUSS Working Group
WRB, 2014) Malau Typic Paleudult Haplic Alisol Allic Paleudult Haplic Alisols (Arenic) Kekura Oxic Dystrudepts Dystric Cambisols Yellow Dystroparalit Haplic Cambisols (dystric) Malacca Typic Hapludox Haplic Ferralsols Typic Hapludox Haplic Ferralsols (clayic) Gajah Mati Typic Kandiudult Haplic Nitisol Typic Kandiudult Haplic Nitisol (dystric)
Terap Typic Kandiudult Haplic Nitisol Typic Kandiudult Haplic Nitisols (dystric) Pedu Typic Kandiudult Haplic Nitisol Typic Kandiudult Haplic Nitisols (dystric) Nerang Typic Kandiudult Haplic Nitisol Typic Kandiudult Haplic Nitisols (dystric) Dampar Typic Kandiudult Haplic Nitisol Typic Kandiudult Haplic Nitisols (dystric) Tebok Typic Kandiudult Haplic Nitisol Typic Kandiudult Haplic Nitisols (dystric) Rasau Typic Paleudult Haplic Nitisol Typic Paleudult Haplic Nitisols (dystric) Nangka Typic Dystrudept Dystric Cambisol Typic Dystrudept Haplic Cambisol (dystric)
Serai Albic
Quartzipsamment Albic Arenosol Albic
Quartzipsamment Albic Arenosol (dystric) Banar Aquic Dystrudept Gleyic Cambisol Aquic Dystrudept Endogleyic Cambisol
(dystric)
Buso Typic Haplohumod Carbic Podsol Lithic Haplohumod Carbic Podsols
3.4. CHEMICAL CHARACTERISTICS
Eight (8) soil profiles representing the Buso Series (S1), Nangka Series (S2), Pedu Series (S3), Serai Series (S4), Nerang Series (S5), Serai Series (S6), Serai Series (S7), Nangka Series (S8) have been described and sampled for soil analyses. The descriptions and analytical data are given in Appendix I. The soils sampled are:
Pedon S1 ― Buso Series (Mouila Lot 3 Estate) Pedon S2 ― Nangka Series (Mouila Lot 3 Estate) Pedon S3 ― Pedu Series (Mouila Lot 3 Extension) Pedon S4 ― Serai Series (Mouila Lot 3 Extension) Pedon S5 ― Nerang/fsl Series (Mouila Lot 3 Extension) Pedon S6 ― Serai Series (Mouila Lot 3 Extension) Pedon S7 ― Serai Series (Ndende Estate)
Pedon S8 ― Nangka Series (Ndende Estate)
Soils of the Buso Series (Pedon S1) are shallow soils with a shallow cemented spodic horizon developed over sub-recent alluvial parent materials. These soils have a clay content of 8% in the surface and increases to 14% with depth. Silt contents are 18-33%
while sand content are 58 to 68%. These soils are acidic with a pH range of 5.20 to 5.84. The organic carbon contents and total nitrogen values are low and decrease with depth. The higher organic carbon content in the subsoil confirm the presence of the spodic horizon Total P values are low while available P values are very low. The exchangeable cations are low and dominated by potassium. The cation exchange capacity values are very low and base saturation values are moderate. The soil analysis data suggest that these soils are of very low fertility status.
Soils of the Nangka Series (Pedon S2) are deep soils developed over alluvial parent materials. These soils have a clay content of 17% in the surface and increases to 21%
with depth. Silt contents are 12-16% while sand content are 65 to 71%. These soils are acidic with a pH range of 4.63 to 5.44. The organic carbon contents and total nitrogen values are low and decrease with depth. Total P values are low while available P values are very low. The exchangeable cations are low but dominated by potassium.
The cation exchange capacity values are low and base saturation values are very low.
Pediments P3 parent materials. These soils have a clay content of 55% in the surface and increases to 57% with depth. Silt contents are 4-6% while sand content are 38 to 41%. These soils are acidic with a pH range of 4.6 to 5.2. The organic carbon contents and total nitrogen values are high and decrease with depth. Total P values are high while available P values are very high. The exchangeable cations are high to low and dominated by calcium. The cation exchange capacity values are moderate but base saturation values are low. The soil analysis data suggest that these soils are of low fertility status.
Soils of the Serai Series (Pedon S4) are deep sandy soils developed over sub-recent alluvium parent materials. These soils have a clay content of 8% in the surface and decreases to 5% with depth. Silt contents are 16-17% while sand content are 76 to 79%.
These soils are acidic with a pH range of 4.9 to 5.6. The organic carbon contents and total nitrogen values are high and decrease with depth. Total P values are low while available P values are also low. The exchangeable cations are low. The cation exchange capacity values are low and base saturation values are also low. The soil analysis data suggest that these soils are of low fertility status mainly due to sandy textures.
Soils of the Nerang/fsl Series (Pedon S5) are moderately deep soils developed over Lateritic Pediments P3 parent materials. These soils have a clay content of 15% in the surface and increases to 22% with depth. Silt contents are 6-8% while sand content are 70 to 79%. These soils are acidic with a pH range of 4.8 to 5.7. The organic carbon contents and total nitrogen values are moderate and decrease with depth. Total P values are low while available P values are very low. The exchangeable cations are low and dominated by magnesium. The cation exchange capacity values are low and base saturation values are also low. The soil analysis data suggest that these soils are of low fertility status.
Soils of the Serai Series (Pedon S6) are deep sandy soils developed over sub-recent alluvium parent materials. These soils have a clay content of 10% in the surface and decreases to 3% with depth. Silt contents are 4-11% while sand content are 86 to 87%.
These soils are acidic with a pH range of 4.1 to 5.7. The organic carbon contents and total nitrogen values are low and decrease with depth. Total P values are low while
available P values are very low. The exchangeable cations are low. The cation exchange capacity values are low and base saturation values are also low. The soil analysis data suggest that these soils are of low fertility status.
Soils of the Serai Series (Pedon S7) are deep sandy soils developed over sub-recent alluvium parent materials. These soils have a clay content of 15% in the surface and changes to 13-15% with depth. Silt contents are 18-22% while sand content are 65 to 67%. These soils are acidic with a pH range of 4.5 to 5.1. The organic carbon contents and total nitrogen values are moderate to low and decrease with depth. Total P values are low while available P values are very low. The exchangeable cations are low and dominated by magnesium. The cation exchange capacity values are low and base saturation values are also low. The soil analysis data suggest that these soils are of low fertility status.
Soils of the Nerang Series (Pedon S8) are moderately deep soils developed over Lateritic Pediments P3 parent materials. These soils have a clay content of 23% in the surface and increases to 32% with depth. Silt contents are 3-9% while sand content are 65 to 72%. These soils are acidic with a pH range of 4.3 to 5.6. The organic carbon contents and total nitrogen values are moderate and decrease with depth. Total P values are moderate while available P values are very low. The exchangeable cations are low and dominated by magnesium. The cation exchange capacity values are low and base saturation values are also low. The soil analysis data suggest that these soils are of low fertility status.
