EFFECT OF CONVERTING WETLAND FOREST TO SAGE PALM PLANTATIONS ON METHANE GAS FLUX AND ORGANIC-CARBON DYNAMICS IN TROPICAL PEAT SOIL

The effect of changing wetland forest to sage palm plantations on meth ane gas flux and organic carbon dynamics in tropical peat soil was stu died in the field and the laboratory using soil samples from the Feat Research Station, Sarawak, Malaysia. A small amount of methane was rel eased from the soil surface of both the forest and plantation held, wi th no significant difference between the two sites (1.1 +/- 0.61 and 1 .39 +/- 0.82 mg CH4 m(-2) hr(-1), respectively); thus, the amount of m ethane emission from the total area of tropical peat soil was estimate d, preliminarily, as 2.43 Tg yr(-1), contributing 0.45% of the total g lobal methane emission and 2.1% of methane emissions from global natur al wetland. However, large amounts of methane were accumulated in the deeper soil layers. Sage palm contained much less carbon as biomass, b ut lost more as the carbon dissolved in groundwater. Laboratory experi ments showed that incorporation of rice straw into tropical peat soil increased methane formation significantly. Conversely, ammonium sulfat e suppressed methane formation in tropical peat soil. (C) 1998 John Wi ley & Sons, Ltd.