Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/12891
Title: Subsidence and carbon loss in drained tropical peatlands
Authors: Hooijer, A.
Page, S.
Jauhiainen, J.
Lee, W.A.
Lu, X.X.
Idris, A.
Anshari, G.
First Published: 2012
Publisher: Copernicus GmbH (Copernicus Publications) on behalf of the European Geosciences Union (EGU)
Citation: Biogeosciences, 2012, 9 (3), pp. 1053-1071
Abstract: Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO[subscript 2] emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 yr after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 yr, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr[superscript −1]. The results confirm that primary consolidation contributed substantially to total subsidence only in the first year after drainage, that secondary consolidation was negligible, and that the amount of compaction was also much reduced within 5 yr. Over 5 yr after drainage, 75 % of cumulative subsidence was caused by peat oxidation, and after 18 yr this was 92 %. The average rate of carbon loss over the first 5 yr was 178 t CO[subscript 2eq] ha[superscript −1] yr[superscript −1], which reduced to 73 t CO[subscript 2eq] ha[superscript −1] yr[superscript −1] over subsequent years, potentially resulting in an average loss of 100 t CO[subscript 2eq] ha[superscript −1] yr[superscript −1] over 25 yr. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and other factors such as addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water levels theoretically possible in plantations. This implies that improved plantation water management will reduce these impacts by 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence are inevitable consequences of conversion of forested tropical peatlands to other land uses.
DOI Link: 10.5194/bg-9-1053-2012
ISSN: 1726-4170
eISSN: 1726-4189
Links: http://hdl.handle.net/2381/12891
http://www.biogeosciences.net/9/1053/2012/bg-9-1053-2012.html
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: © Author(s) 2012. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Appears in Collections:Published Articles, Dept. of Geography

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