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| Titel |
Soil carbon dioxide and methane fluxes from lowland forests converted to oil palm and rubber plantations in Sumatra, Indonesia |
| VerfasserIn |
Evelyn Preuss, Marife D. Corre, Muhammad Damris, Aiyen Tjoa, Sri Rahayu Utami, Edzo Veldkamp |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111303
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| Publikation (Nr.) |
 EGU/EGU2015-11408.pdf |
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| Zusammenfassung |
| 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 for the next ten
years. This agricultural expansion is achieved by conversion of rainforest. Land-use
conversion affects soil carbon dioxide (CO2) and methane (CH4) fluxes through
changes in nutrient availability and soil properties which, in turn, influence plant
productivity, microbial activity and gas diffusivity. Our study was aimed to assess
changes in soil CO2 and CH4 fluxes with forest conversion to oil palm and rubber
plantations. Our study area was Jambi Province, Sumatra, Indonesia. We selected two
soil landscapes in this region: loam and clay Acrisol soils. At each landscape, we
investigated four land-use systems: lowland secondary rainforest, secondary forest with
regenerating rubber (referred here as jungle rubber), rubber (7-17 years old) and
oil palm plantations (9-16 years old). Each land use in each soil landscape was
represented by four sites as replicates, totaling to 32 sites. We measured soil-atmosphere
CH4 and CO2 fluxes using vented static chamber method with monthly sampling
from November 2012 to December 2013. There were no differences in soil CO2
and CH4 fluxes (all P > 0.05) between soil landscapes for each land-use type.
For soil CO2 fluxes, in both clay and loam Acrisol soil landscapes oil palm were
lower compared to the other land uses (P < 0.007). In the clay Acrisol, soil
CO2 fluxes were 107.2±Â7.2 mgÂCÂm-2Âh-1 for oil palm, and 195.9±Â13.5
mgÂCÂm-2Âh-1for forest, 185.3±Â9.4 mgÂCÂm-2Âh-1for jungle rubber and
182.8±Â16.2 mgÂCÂm2Âh-1for rubber. In the loam Acrisol, soil CO2 fluxes were 115.7
±Â11.0ÂmgÂCO2-C m2Âh-1 for oil palm, and 186.6±Â13.7, 178.7±Â11.2, 182.9 ±
14.5 mgÂCO2-CÂm-2Âh-1 for forest, jungle rubber and rubber, respectively. The
seasonal patterns of soil CO2 fluxes were positively correlated with water-filled
pore space (WFPS) in loam Acrisol jungle rubber (P < 0.05), and positively
correlated with soil temperature in loam Acrisol forest (P < 0.05) andclay Acrisol
oilÂpalm (P < 0.01). For soil CH4 fluxes, in the clay Acrisol CH4 uptake was
highest in the forest (40.3±Â10.3 μgÂCH4-CÂm-2Âh-1)followed by the jungle
rubber (20.8±Â7.2 μgÂCH4-CÂm2Âh-1) and both were higher than in the rubber
(3.0±Â1.3 μgÂCH4-CÂm-2Âh1) and oil palm (6.4±Â3.1 μgÂCH4-CÂm-2Âh-1) (P =
0.005). In the loam Acrisol, two out of four forest plots generally showed net CH4
emissions, resulting to a large variation around the mean CH4 flux from the forest (1.6 ±
17.1 μgÂCÂm-2Âh-1); comparing only the three land uses, a similar trend was
observed as that in the clay Acrisol: larger CH4 uptake in jungle rubber (26.9 ± 3.9
μgÂCÂm-2Âh-1) than in rubber (9.7 ±Â3.8 μgÂCÂm-2Âh-1) and oil palm (14.9±Â3.1
μgÂCÂm-2Âh-1). The seasonal patterns of soil CH4 fluxes for each land use and soil
landscape were all positively correlated with WFPS (all P < 0.05). Across landscapes
and land uses, annual soil CH4 fluxes were correlated with soil fertility index (r =
-0.38, P = 0.04, n = 32). Conversion of forest to oil palm and rubber plantations
decreased soil CO2 fluxes and CH4 uptake mainly due to changes in soil moisture,
temperature and fertility. These changes in soil trace gas fluxes should be considered
in the greenhouse gas life-cycle analysis of these economically important crops. |
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