Mapping the Characteristics of Tropical Forest Peat and Cultivated Peat Under Oil Palm Plantation in Sarawak, Borneo

Abstract

This study attempts to establish and map the characteristics of peat soil under oil palm plantation and forest ecosystem. Peat soil from oil palm plantation and forest was collected for analysis at the depths of 0-15 cm, 100 cm, 200 cm and 300 cm. The plantation peat was found richer with exchangeable calcium and potassium likely due to the fertilisation and liming practices at the estate. The carbon dioxide (CO 2) flux was detected higher at the plantation with elevated emission recorded near the drainage canal. As the depth increased, moisture was evidenced to surge with declining bulk density, indicative of less decomposed underlying peat. The E 4 /E 6 values, however, did not reveal any statistical difference in peat soil from different land use and depths. The carbon-to-nitrogen (C/N) ratio was found lower in the cultivated peat suggesting reduced nitrogen stores. This was likely associated with the plantation management practices, resulting in enhanced mineralisation of nitrogen. The C/N ratio was evidenced to increase with increasing depths in both plantation and forest, indicative of lower humification degree for the horizon peat. It was concluded that the soil characteristics differed between land use and depths with spatial variations within each land use.