Soils of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates, Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon, Africa
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EXECUTIVE SUMMARY
INTRODUCTION
This semi-detailed soil survey and assessment report of MOUILA LOT 3, MOUILA LOT 3 EXTENSION & NDENDE ESTATES located in the Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon, Africa totalling 25,803.0 ha most of which has been planted with oil palm was carried out in October 2018. The Estate consists of land which belongs to OLAM PALM GABON S. A. The study was carried out by PARAM AGRICULTURAL SOIL SURVEYS (M) SDN. BHD. The Estate which is situated to the east and west of the Mouila - Ndende Highway. The three parcels occur south of Mouila and north of Ndende.
PURPOSE OF THE STUDY
The purpose of the study was to produce a semi-detailed soil map of the Estates at a scale of 1:25,000 and to characterize the soils in the Estates with a view of grouping the soils into management groups for oil palm cultivation and to highlight problems if any, in their management. Such improved management practices it is hoped will help increase sustainability, productivity and economic returns. These soil maps will assist the Estate to be certified under the Roundtable for Sustainable Palm Oil (RSPO) or other similar certification schemes.
TOPOGRAPHY AND DRAINAGE
The Estates has land with slopes of level, undulating and rolling (0-24% or 0-12°) terrain.
Most of the upland areas are well to moderately well drained but the river floodplains are well drained to imperfectly drained. The elevation in the Estate is 100 to 200 meters (300 to 600 feet) above mean sea level.
GEOLOGY AND GEOMORPHOLOGY
The study area consists mainly of dolomite, limestone, claystone and sandstone Rocks of Upper Precambrian age. The area consists of level to rolling terrain.
Soils of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates, Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon, Africa
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The climate in the area was mainly assessed using data from Mouila Lot 3, MOUTASSOU -Station 1, Estate 12 and NDENDE -Fera Station, Estate 18 for the period 2016-2018 (2019- incomplete year). The MOUTASSOU -Station 1, Estate 12 has a total annual rainfall of between 1,253 mm to 1,515 mm per annum with an occasional dry month. The total annual raindays is 170 to 183 days. The three-year means are 1,455 mm and 182 days.
The NDENDE -Fera Station, Estate 18 has a total annual rainfall of between 1,348 mm to 1,650 mm per annum with an occasional dry month. The total annual raindays is 124 to 174 days. The three-year means are 1,501 mm and 156 days.
About four dry months (<100 mm) commonly occur in the months of June, July, August and September but this varies from year to year in both Mouila Lot 3, MOUTASSOU -Station 1, Estate 12 and NDENDE -Fera Station, Estate 18 areas.
SOILS
A total of twenty-five (25) soil mapping units consisting of sixteen (16) soil series as defined in Malaysia were identified in the Estate. These soil series consist of soils developed over Sedimentary Rocks, Pediments (P, P3 and P2) and Sub-Recent Alluvial Deposits. A semi- detailed soil map of the Estates at a scale of 1:25,000 has been produced. A summary of the main characteristics of the soil types is given in Table 3.1 and in the soil map legend.
SOIL MANAGEMENT
The results of the soil survey indicate that the soils in the Estates can be placed into seven (7) Soil Management Groups. All of these Groups are Mineral Soil Groups. These groups are based on the soil depth, textural class, drainage class and fertility status of these soils. All the soils in the Estate are of low fertility status. The main limitations and management practices recommended for the seven (7) groups is given in Table 4.4. Many of these recommended practices are already being carried out but these can be further fine-tuned and monitored regularly. If these practices are fully implemented an overall peak yield of 28-32 mt/ha/yr and 26-30 mt/ha/yr or more should be obtainable in the soils of Groups A and B respectively.
However, this would depend on the rainfall and slope class. On the poorly drained soils of Group C a peak yield potential of 28-34 mt/ha/yr can be expected. On the sandy soils of Group D a peak yield potential of only 18-24 mt/ha/yr can be obtainable. However, on the
Soils of Mouila Lot 3, Mouila Lot 3 Extension & Ndende Estates, Mougalaba, Douya Onoye & Dola Departments, Ngounie Province, Republic of Gabon, Africa
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petroplinthic/lateritic soils of Group P a peak yield of only 22-28 mt/ha/yr can be expected.
These yields however would depend on the level of management practiced, rainfall distribution and the type of planting material used.
