Soil Profiles: Ulu Dong
Ulu Dong Series
The Ulu Dong Series is a member of the family of very fine, kaolinitic, isohyperthermic, red Tipik Lutualemkuts. It is developed over quartz-mica-schists. They are characterized here by their deep kandic horizons with a clay content of more than 60% with no significant decrease to 100 cm of the soil surface and their red to yellowish red colours. Structures are weak medium and coarse subangular blocky and consistence is friable. Patchy clayskins occur on ped faces. The CECclay is less than 16 cmol (+) in all horizons between 25 to 100 cm of the soil surface.
Type Location
The Ulu Dong Series were first described and studied by Lim (1977) near Dong village to the east of Raub. The above pedon was also described by Lim during the Detailed Reconnaissance Soil Survey of the KESEDAR Region, Ulu Kelantan (Lim et al. 1980) at the 57 km (36 milestone) Tanah Merah to Batu Melintang Road over quartz-mica-schists at an elevation of 103 m (340 feet) under secondary forest on hilly terrain. Location: Topographic Sheet 3867, 5°49′ N, 102°00′ E (Grid Reference 3867 – 440430 m).
Range in Characteristics
Little is known about the range in characteristics of the Ulu Dong Series. The main characteristics are that these soils must be deep and have a clay content of over 60% and the clay content should not decrease from the maximum by more than 20% within 100 cm of the soil surface. Some soils with about 55% clay have also been mapped as Ulu Dong Series in the past. Colours in the subsoils belong to the red colour class. Subsoil colours range from yellowish red (5YR4/6, 5/6, 5/8) to red (2.5YR3/6, 4/6, 4/8, 5/6, 5/8, 6/6, 6/8) to light red (2.5YR7/6, 7/8). The colours normally become redder with depth. Structures are weak coarse and medium subangular blocky and consistence is friable. Clayskins occur on ped faces. Mottling is rare and if present is faint.
Competing Soils and Their Differences
Soils of the Ulu Dong Series are likely to be confused with other red-coloured soils which have heavy clay (> 60% clay) textures. These include soils of the Patang, Prang, Kampong Kolam, Apas, Tarat and Sagu Series. All these soils have an oxic horizon while the Ulu Dong Series has a kandic horizon. The Langkawi Series over limestone has many properties similar to the Ulu Dong Series. The Ulu Dong Series generally has lower clay contents and some sand while the Langkawi Series higher clay content and virtually no sand. In Sabah no red-coloured soils with a deep kandic horizon have been mapped but some soils mapped as the Kumansi Series/deep/red variant may have some features similar to the Ulu Dong Series but the Kumansi Series normally have a CECclay of more than 24 cmol (+) kg–1 clay. Soils of the Chat Series (CECclay less than 16 cmol, red-yellow colour class), Melugu (CECclay 16–24 cmol, red-yellow colour class) and Stass (CECclay more than 24 cmol, red-yellow colour class) are similar textured but differ in CECclay values and subsoil colours. The Jakar Series has red colours but has 35–60% clay and a CECclay of more than 24 cmol.
Setting
Soils of the Ulu Dong Series to-date have been mapped on rolling, hilly to steep terrain (slopes in excess of 12% or 6°) at elevations of 30 m to over 200 m (100– 700 feet).
Principal Associated Soils
The Ulu Dong Series has been mapped in association with soils of the Chat Series (CECclay less than 16 cmol, red-yellow colour, clay content more than 60%). Occasionally they have also been mapped in association with soils of the Bungor Series (CECclay less than 16 cmol, clay content 35 to 60%, red-yellow colour class).
Drainage and Permeability <
Soils of the Ulu Dong Series are deep, well drained soils with a good permeability.
Use and Vegetation
Rubber, fruit trees and oil palm are the commonest crops grown on soils of the Ulu Dong Series. Some of these soils may still be under primary forest.
Distribution and Extent
Soils of the Ulu Dong Series have to-date been only mapped in the states of Kelantan, Pahang and Johor. Their actual extent is not fully known.
Series Established
The series was established by Lim (1977) during soil surveys in Pahang State. The source of name is the Kampong Ulu Dong off the Raub-Benta road, Pahang State, Peninsular Malaysia.
Remarks on Classification
Soils of the Ulu Dong Series are classified here according to the Malaysian Soil Taxonomy – Second Approximation (Paramananthan 1998) as a member of the very fine, kaolinitic, isohyperthermic red family of Tipik Lutualemkuts. They are classified as deep, well drained soils having a kandic horizon with red colours and a clay content in excess of 60%. In the Keys to Soil Taxonomy – Eighth Edition (Soil Survey Staff 1998) soils of the Ulu Dong Series are probably classified as Typic Kandiudox. In the FAO/UNESCO Soil Map of the World – Revised Legend (FAO 1990) these soils would probably be Haplic Nitisols.
Suitability for Agriculture
Soils of the Ulu Dong Series are probably suitable for a wide range of crops with proper management. The slope on which these soils occur, their low fertility status and phosphorus fixation are the main limitations. With good management these soils should be suitable for a wide range of crops such as oil palm, rubber, fruit trees, pepper and cocoa.
