Peat Soils of Malaysia: Their Extent, Characteristics, Mapping, and Classification*

摘要

Organic soils are estimated to occupy about 2.8 million hectares in Malaysia of which about 1.8 million hectares occur in Sarawak and about 0.8 million hectares in Peninsular Malaysia and about 0.2 million hectares in Sabah. The mapping, classification and cultivation on these organic soils have lagged far behind those of mineral soils.Most organic soils occur between the coast and the hills in the hinterland and typically form domes with a distinct zonation from the edges to the centre. Thus their original vegetation, chemical and physical properties also have the zonal effect.In the past the mapping of peats used their depth and loss on ignition as the main criteria. No attempts were made to differentiate the different types of organic soil materials and the presence/absence of wood in their mapping and classification. Past soil maps and classification systems thus did not adequately describe and characterise these soils and thus caused a lack of understanding of how to manage them. Current mapping and classification of organic soils in Malaysia takes into consideration thestage of decomposition ofthe organic soil material - sapric, hemic, fibric; the presence/absence ofwood - decomposed or undecomposed; their depth and the nature of the underlying substratum/mineral materials. This new proposed classification system has been used to map about 0.5 million hectares of organic soils in Malaysia to-date.The paper concludes with some recent findings and their implications to the oil palm industry. Gaps in our knowledge are also highlighted.