Abstract
Conversion of tropical peatland into oil palm plantation in Southeast
Asia has been alleged to have increased the decomposition process via peat oxidation
due to drainage and water management, raising the emission of soil CO₂ . This is
postulated to increase with age of oil palm cultivation. However, management also
plays a role in soil CO₂ emissions from oil palm plantations. The objective of this
study was to determine the controlling factors infl uencing soil CO₂ fl uxes in different ages of oil palm on tropical peatland. The soil CO₂ fl uxes were measured for
24 months from three palm ages (1, 5 and 7 years palm; S1, S2, S3) in tropical
peatland of Sarawak, Malaysia using a closed-chamber method. The highest mean
soil CO₂ fl ux was recorded in S3 (221 mg C m -2 h -1 ) followed by S2 (195 mg C m -2 h -1 )
and S1 (178 mg C m -2 h -1 ) palms. The cumulative soil CO₂ fl uxes for S1, S2 and S3
were 14.7, 16.4 and 18.5 t C ha -1 year -1 , respectively. Water table was found to have
no correlation with soil CO₂ fl uxes but water-fi lled pores space (WFPS) correlated
negatively with soil CO₂ fl uxes in all three different ages of oil palm. The increase
in soil CO₂ fl ux with palm age was consistent with higher root biomass, suggesting
that root respiration and microbial activity were associated with root exudates as
major component of soil respiration in tropical peatland under oil palm.
