B31E-02
CO2 and CH4 fluxes from oil palm plantations in Sumatra, Indonesia: effects of palm age and environmental conditions

Wednesday, 16 December 2015: 08:15
2004 (Moscone West)
Ana Meijide1, Evelyn Hassler2, Marife D Corre2, Tania June3, Edzo Veldkamp4 and Alexander Knohl4, (1)University of Göttingen, Bioclimatology, Göttingen, Germany, (2)Georg-August University of Göttingen, Soil Science of Tropical and Subtropical Ecosystems, Büsgen Institute, Göttingen, Germany, (3)Bogor Agricultural University (IPB), Department of Geophysics and Meteorology, Bogor, Indonesia, (4)University of Göttingen, Göttingen, Germany
Abstract:
Global increasing demand of palm oil is leading to the expansion of oil palm plantations, particularly in SE Asia, which in Sumatran lowlands has resulted in a 21% forest area loss. Large photosynthesis rates are expected for oil palms, due to their high growth and yield production. However, there is very limited information on their effect on carbon dioxide (CO2) fluxes and their sink or source strength at ecosystem scale. For methane (CH4) fluxes, research has mainly focused in oil palm plantations located on peatlands, but no information is available at ecosystem level from plantations on mineral soils.

With the aim of studying CO2 fluxes during the non-productive and productive phases of oil palm cultivation, an eddy covariance (EC) tower was installed in a 2 year old oil palm plantation, where it was measuring for 8 months, and was subsequently moved to a 12 year old plantation, both in the province of Jambi, Sumatra. The EC system consisted of a Licor 7500A and an ultrasonic Metek anemometer, operating at 10 Hz, installed on a 7m and 22m tower respectively. In the 12 year old plantation, the tower was also equipped with a Los Gatos FGGA-24EP, to assess CH4 fluxes. Chamber measurements were also carried out to obtain information on respiration and CH4 fluxes from the soil.

Radiation was the major driver controlling net carbon uptake, while soil moisture did not play a significant role. Average net ecosystem exchange in the hours of the day with higher radiation for the whole measurement period was 10 µmol m-2 s-1 for the 2 year old plantation and -22 µmol m-2 s-1 in the 12 year old. The analysis of the cumulative fluxes show that the non-productive plantation was a carbon source of around 636 g CO2 m-2 during the 8 months of measurements, while in the productive period, it acted as a strong carbon sink (-794 g CO2 m-2 yr-1). Methane uptake was observed in the soil in both plantations and also for the whole ecosystem in the 12 year old one, but its contributions to the global greenhouse gas budget was very limited in relation to that of CO2. These results reveal the strong contrast between young non-productive and mature productive oil palm plantations, thus highlighting the need of evaluating all stages of development of oil palm plantations when assessing their carbon balance at regional scale.

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