A Study of Floral Composition of Peat Soil in the Lower Batang Hari River Basin of Jambi, Sumatra(<Special Issue>Problem Soils in Southeast Asia)

Abstract

Pollen diagrams have been prepared of three sections of peat soil deposits from different localities on the coastal swampy land of Jambi in order to study the vegetational change from the basal clay to the present-day forest. The age of peat soil deposits was determined by ^<14>C dating of peat layers. The existence of arboreal and non-arboreal pollen types in the main portion of the peat soil deposits in the study area indicates the change from fern association in the bottom layer to the swamp forest in the upper layer. However, the floral composition of these soils indicates a difference in environment between the center zone and the zone transitional to the coastal zone. In the center zone of the Kumpeh area, the peat swamp was inundated by fresh water in all layers, which are characterized by an abundance of ferns in the bottom layer, by many kinds of arboreal pollen types in the upper layer, and by a uniform pollen type between these layers. In the center zone of the Tanjung area, the peat swamp was inundated by fresh water in the upper layer and brackish water in the bottom layer. In the zone transitional to the coastal zone the peat swamp was inundated by brackish water in all layers. The floral composition of peat soil inundated by brackish water is mostly derived from mangrove vegetation. Peat accumulation in the study area is thought to be related to water inundation during the transgression period.