Abstract:

Oil palm plantations have dramatically expanded in tropical Asia over the past decades. Although their establishment has been projected to increase nitrous oxide (N₂O) emissions, earlier reports have shown inconsistent results. This study analyzed these previously published data to compare N₂O emissions in oil palm plantations to reference forests. A linear mixed-effects model was used to examine the significance of the effect of establishing oil palm plantations on N₂O emissions, rather than to calculate mean effect sizes because of limitations in the data structure. The results indicated that N₂O emissions were significantly greater from oil palm plantations than from reference forests, as expected. This is the first study to report the effect of oil palm plantations on N₂O emissions by synthesizing previously published data. To quantify the size of this effect, additional studies with frequent and long-term monitoring data are needed.

Key words: Meta-analysis, Nitrogen fertilization, Nitrous oxide, Oil palm plantation, Tropical forest