Soil carbon dioxide and methane fluxes from lowland forests converted to oil palm and rubber plantations in Sumatra, Indonesia

Evelyn Preuß1, Marife Corre1, Edzo Veldkamp1
1 Soil Science of Tropical and Subtropical Ecosystems, Büsgen Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.

P 3.18 in Fluxes between the atmosphere and ecosystems

Poster Session 2 on Tuesday, 16:30-18:00

Demand for palm oil has increased strongly in recent decades. Global palm oil production quadrupled between 1990 and 2009, and although almost half of the global supply is already produced in Indonesia, a doubling of current production is planned. Furthermore, Indonesia is the second largest rubber producer in the world and global demand for rubber is high. Land-use changes are known to influence soil carbon dioxide (CO2) and methane (CH4) fluxes. Although most of Indonesian palm oil and rubber is generated in Sumatra, greenhouse gas measurements from oil palm and rubber plantations are scare in this region. Our study was aimed to assess changes in soil CO2 and CH4 fluxes with rainforest conversion to oil palm and rubber plantations. Our study region was in Jambi province, Sumatra, Indonesia, where forest conversion to oil palm and rubber is widespread. We measured soil-atmosphere CH4 and CO2 fluxes using vented static chamber method for thirteen months (November 2012 to December 2013). The study region was delineated into two soil landscapes: sandy loam and clay Acrisol soils. At each landscape, we selected four land-use systems: lowland rainforest (as reference land use), rubber interspersed in naturally regenerating secondary forest (referred here as jungle rubber), and monoculture plantations of rubber (7-17 years old) and oil palm (9-16 years old). Each land-use system was represented by four sites (as replicates), and measurements were conducted within a 50 m x 50 m area of each site. In both soil landscapes, soil CO2 fluxes from oil palm were lower compared to the other land-use systems (P = 0.0068). In the clay Acrisol, soil CO2 fluxes were 107.2 ± 7.2 mg C m-2 h-1 for oil palm, and 195.9 ± 13.5 mg C m-2 h-1 for forest, 185.4 ± 9.4 mg C m-2 h-1 for jungle rubber and 182.8 ± 16.2 mg C m‑2 h-1 for rubber. Similar trend was observed in the sandy loam Acrisol: 115.7 ± 11.0 mg CO2-C m‑2 h-1 for oil palm, and 186.6 ± 13.7, 178.7 ± 11.2, 182.9 ± 14.5 mg CO2-C m-2 h-1 for forest, jungle rubber and rubber, respectively. For soil CH4 fluxes, in the clayey Acrisol, CH4 uptake in the forest (‑40.3 ± 10.3 µg CH4-C m-2 h-1) was higher (P = 0.0041) than in the rubber (‑3.0 ± 1.3 µg CH4-C m-2 h‑1) and oil palm (‑6.4 ± 3.1 µg CH4-C m-2 h-1) but comparable to jungle rubber (‑20.8 ± 7.2 µg CH4-C m‑h-1). In the sandy loam Acrisol, there were no significant differences in CH4 uptake among land-use systems with fluxes of ‑1.6 ± 17.1, ‑26.9 ± 3.9, ‑9.7 ± 3.8, ‑14.9 ± 3.1 µg C m-2 h-1 for forest, jungles rubber, rubber and oil palm plantations, respectively. Our results showed that conversion of rainforest to monoculture systems of oil palm and rubber plantations altered soil CO2 and CH4 fluxes and hence should be considered in the greenhouse gas life-cycle analysis of these economically important crops.

Letzte Änderung 04.04.2014