EFFECT OF FOREST TYPE ON DECOMPOSITION RATE AND GREENHOUSE GAS FLUXES OF TROPICAL PEAT SOIL AFTER CONVERSION INTO AN OIL PALM PLANTATION

摘要

The effect of forest type on the decomposability and greenhouse gas fluxes of tropical peat soils after conversion to an oil palm plantation was evaluated through a field incubation experiment of peat soils from three representative types of primary forest in Sarawak, Malaysia, namely Mixed Peat Swamp (MPS), Alan Baru (ABt), and Alan Bunga (ABg). Carbon dioxide (CO2) and methane (CH4) fluxes were measured on a monthly basis for 36 months. The CO2 and CH4 fluxes ranged from 78-625 mg C m~(-2) h~(-1) and -67-653 p.g C ~(-2) h~(-1), respectively. Both of CO2 and CH4 fluxes were larger in the order ABg > ABt > MPS, which corresponded to the relative abundance of O-alkyl C derived mainly from polysaccharides in soil organic matter (SOM). Rate of decomposition of peat was almost constant during the 3-year period, and annual decomposition rate was estimated to be 0.033 y~(-1) for MPS, 0.048 y~(-1) for ABt. and 0.066 y~(-1) for ABg.