The influence of nitrogen (N) fertilizer in the early growth stage of sago palms intercropped with taro was investigated using 3 types of fertilizer at 3 levels. The applied fertilizers were the slow-release fertilizers Meister 40 (M40) and Meister 70 (M70) and urea. The application rates of each fertilizer were 50 kg N ha^-1, 100 kg N ha^-1, and 150 kg N ha^-1, respectively. The plant height and leaf number of sago palm were monitored from 25 July 2005 to 20 December 2006. The growth rate was defined as the plant height increase during the half year adjusted by the number of days of the investigation period. Taro plants were harvested from 5 to 12 January 2006.
 The dry matter yield of Taro was 1,637 to 2,080 kg ha^-1. Taro showed higher N accumulation in all fertilized treatments than in the control, but no significant difference was observed due to high variability in individual plants. Due to the initial difference and high variability in sago palms within one treatment, no clear influence of different fertilizer types and application rates on change in average height and leaf number could be determined. However, the growth rate tended to be lower with higher fertilizer application rate than with lower rates in the 1st phase (25 July 2005 to 30 November 2005) and the 3rd phase (26 July 2006 to 20 December 2006), especially for slow-release fertilizer treatments. The growth rate in the 2nd (30 November 2005 to 26 July 2006) and 3rd phases ranged from 27 to 87 cm half year^-1 and was higher than that in the 1st phase, when it ranged from 8 to 31 cm half year^-1. The sago palm growth rate was inhibited under a N application rate of 150 kg N ha^-1, while a low fertilizer application of 50 kg N ha^-1 showed an enhanced growth rate.

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Methane (CH₄) and carbon dioxide (CO₂) fluxes from tropical peat soils were compared between sago palm (Metroxylon sagu Rottb.) cultivation blocks with different plant ages (3, 5, and 7 years old) and their neighboring secondary forests. No significant variations in CH₄ and CO₂ fluxes were observed during the daytime. The mean values of CH₄ flux from sago palm soils and secondary forest soils were 25−44 and 23−30 μg C m^-2 h^-1, respectively. Methane emissions did not differ significantly between each sago palm block and the adjacent secondary forest. The number of years after sago palm transplantation and the development of sago palms were not major factors contributing to the spatial variation in CH₄ flux. The mean values of CO₂ flux from sago palm soils were 43−88 mg C m^-2 h^-1, and those from the secondary forest soils were 44−64 mg C m^-2 h^-1. The CO₂ emissions from a sago palm block with 3-year-old plants were larger than those from the adjacent forest soil. However, the CO₂ emissions from blocks with 5- and 7-year-old sago palms were smaller than those from the 3-year-old sago palm block and did not differ from the CO₂ emissions from the adjacent forest soils.

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