Field Site Description

The Sook Plain has been chosen for the 2001 SLUSE field course through consultation with the relevant  Sabah State Government agencies. The site is considered to be a very relevant and interesting ground for SLUSE field course because of a complex land tenure situation with villages inside forest reserves, unsuccessful agricultural settlement schemes, prevailing (upstream) land use and (downstream) water resource conflicts and a general perception of the area as being poor and under developed.  The plain is considered to have a high but under-utilized agricultural potential. 

Geographical location and accessibility


The Sook Plain is located in Sook sub-district east of Keningau in the Interior District of Sabah (See maps below). The sub-district administrative centre nearest to the field course area is Pekan Sook. This small town is conveniently accessible by road (ca. 42 km) from the district administrative centre, Keningau located 170 km to the southeast of Sabah state capital, Kota Kinabalu.

Geology and geomorphology 

The Padas River catchment where the Sook Plain is located, is underlain by sedimentary rocks that were deposited in the Northwest Borneo geosyncline. These rocks are grouped as (a) the Crocker Formation and (b) the Temburong Formation. The Crocker Formation occupies the greater part of the area whilst the Temburong Formation which occurs as lenses interdigitating with the Crocker Formation, is observed only in the west and south-western corner of the area.  The main difference between the two formations is that the Crocker Formation has relatively greater proportions of arenaceous rocks than the Temburong Formation, in which argillaceous rocks predominate.  The Crocker Formation was deposited during Eocene-Miocene times, while the Temburong Formation during Oligocene-Miocene times. 

Along the major rivers, alluvium is present. The alluvial deposits are grouped as (a) High-Level (Terrace) Alluvium and (b) Recent Alluvium, both of which overlie the earlier-mentioned sedimentary formations. The High-Level Alluvium, which occurs on terraces, was deposited during Late Pliocene. The Recent Alluvium is confined to the river valleys and their flood plains. 

The Sook Plain is characterized by extensive deposits of Recent Alluvium which contains clay (ca. 54%), silt (ca. 40%) and sand (ca. 6%).  This deposit, though occurring near base-level and hence relatively stable could pose problems, especially under uncontrolled logging activities, heavy rainfall, high river-flow and even river capturing at the water-gap areas.



Soil classification and resources 

Soil mapping in Malaysia is carried out by the Department of Agriculture according to pedological properties. In Sabah, the FAO-UNESCO soil classification system is used, in contrast to Peninsular Malaysia and Sarawak, where the US Soil Taxonomy is employed. A typical soil in the humid tropic climate of Borneo influenced by the Monsoon (see climate section) is the Acrisol type and the alluvial paddy soils in river plains. The acrisols are poor in  plant nutrients due to leaching for a very long period, which has created clay minerals with low CEC and high P-immobilization.


The climate of Sabah is equatorial, that is: relatively uniform temperatures in the range 23 to 28C, high humidity (80-85 %) and abundant rainfall. The dominant influences on the climate are the northeast monsoon from November to March and the southwest monsoon between May and September. 

It has been a well documented trend that the Interior Districts of Sabah receives significantly less rainfall compared to the West Coast Region. A 1976 report gave a mean annual rainfall of 2,500 – 4,000 mm for areas west of the Crocker Range, whereas areas east of this range recorded annual rainfalls of only  between 1,500 – 2000 mm. A 29-year (1969-1998) monthly rainfal record for Keningau (in millimeter) is given.

Watershed hydrology and erosion 

Sediments eroded from the geologically young catchment originate from river bank erosion, which can be substantial at high discharge rates during the wet seasons, and from land surfaces, depending on the land use type within the catchment. Suspended matter in rivers pose a severe problem for organic life (e.g. coral reefs in the coastal zone near the river outlet) in aquatic environments by reducing solar radiation needed for photosynthesis. It may also damage fishery. Finally, stream capacity of the rivers and streams can be reduced due to sedimentation and it may cause mechanical damage to installations such as pumps, turbines etc. 

The Sook Plain is drained by the Sook River system originating from the Trus Madi Range. The Sook River catchment has a total area of 1684 sq km, representing 22% of the total Padas River watershed (the second biggest watershed in Sabah). The Sook River flows southwards through largely lacustrine/recent alluvium deposits, and discharges to the main Padas (Upper Pegalan) River near Keningau. 

Several studies have been performed to analyze the influence of land use on sediment yields for Sabah catchments. Studies on the amounts and sources of suspended solids in the Padas river in the southern part of Sabah show that almost half of the sediment load originates from the Tenom valley, underlining the importance of river bank erosion. The impact of land use within the watersheds feeding the Padas River on sediment contribution to streams and rivers is not well known, but a study carried out in 1984 indicated that the Sook River contrubuted approximately 11.3% and 4.6% of the total flow and total sediment load to Lower Pegalan.



Flora and fauna 

Sabah is part of the Malaysian botanical zone which has one of highest species diversity in the World (Whitmore 1984). The natural vegetation in the area is tropical rain forest with lowland mixed Dipterocarp forest and montane rain forest. Plant diversity is particularly high because of the differences in altitude. The fauna is typical of Bornean rain forests with wild boar, various deer and monkeys as the major mammal species. Species diversity is typically lower in the higher altitudes. However, not much undisturbed forest exist in the Sook area, which has been exposed to long term settlement, logging and plantation development.


The population in the Sook catchment area is a mix of original Murut people and newly settled people coming from all over Sabah, and especially from the Dusun community (both Christian and Muslim). The villages identified for the study are all located in Sook Sub-District which contains about 17000 inhabitants. The Dusun are usually associated with the Kadazan in the population statistics, and constitute almost a third of the total population of Sabah. The Murut are a much smaller group, but they share many common important cultural features with the Kadazan-Dusun. The Dusunic and Murutic linguistic families (which comprise many different dialects) belong to the Bornean stock, which is part of the North-Western Austronesian superstock. 

The kinship system of the Dusun is cognatic (bilateral), although the patrikin are considered to be slightly closer than the matrikin. The political structure is basically egalitarian; the headmen are chosen by consensus, and their position is not hereditary. Today, the most important social units are the nuclear family (production unit), the extended family (health care, social security and solidarity, rites of passages, healing rituals, communal work), and the village (annual rituals, such as harvest festival, skull ceremony, etc.) 

The high dependency of Dusun and Murut on agriculture and forest products is traditionally reflected in the religious significance of rice and forests. The environment is traditionally perceived as inhabited by various spirits, living in springs, trees, caves, rainbow, disguised in animals, etc. Some of these spirits are bad, causing misfortune and illness, while others are good and can help humans to fight against bad spirits. Many encounters with animals are interpreted as good or bad omens. People respect a number of taboos, which are either linked to the presence of spirits in some places or to Adat (“custom”, a complex set of laws and rules structuring the society and defining the morality and the good behaviour). The major rituals are linked to the agricultural activities and to the rice cycle (prayers and offerings to the spirits before clearing a field, offerings to the “spirit of the rice”, thanksgiving, purification and restoration rituals, etc.). People also have an extended knowledge of the healing characteristics of plants, but this knowledge is generally shared and is not specialised.

Land and forest use 

The southern part of the Sook Plain is dominated by the Sook Plain Forest Reserve. This reserve is classified as class 2 (i.e. as an amenity forest reserve), and it has been gazetted as a forest reserve after people had settled in the area. Several villages are located within the boundary of the plain and practice shifting cultivation and cash crop farming of taro (known as yam, Colocasia esculenta). To the east of the Reserve, the Youth Resettlement Scheme occupies a large tract of land. Further north, in the Sook valley, villages have settled on State land during the past 100 years and practices subsistence farming and cash crop production. Here the valley is bordered by a Forest Reserve to the east, whereas large scale private oil palm plantations border the valley on the western side. The northernmost reaches of the Sook River are in the Trusmadi Forest Reserve and land use appears to be dominated by logging, perhaps oil palm and smallholder farming. 

The total land area of the Sook sub-division is about 204000 ha, of which approximatively half is suitable for agriculture. 7400 ha of land has already been titled. The population of the district is more than 17000 people (3/4 of them being primarily farmers). The annual rainfall is close to 2000 mm per year. In 1999, the following crops were grown in Sook: 

Rubber 4210 ha Cocoa 400 ha Coffee 84 ha
Oil palm 7315 ha Fruit trees 136 ha Oranges 17 ha
Banana 98 ha Hill rice 650 ha Wet rice 349 ha
Maize 19 ha Groundnut  5 ha Water melon 10 ha
Vegetables 36 ha Cassava 5 ha Yam (taro) 51 ha


The agriculture department is responsible for extension work (transfer of knowledge, educating farmers to modern and sustainable farming techniques), and for the development of agriculture in the area, providing subsidies (seeds, fertilizers, etc.) to farmers for different types of crops. It is also animating women’s groups in almost every villages, teaching them sewing, cooking, and cultivating vegetables.


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