Soil carbon turnover and sequestration in native subtropical tree plantations

Richards, A. E., Dalal, R. C. and Schmidt, S. (2007) Soil carbon turnover and sequestration in native subtropical tree plantations. Soil Biology & Biochemistry, 39 8: 2078-2090. doi:10.1016/j.soilbio.2007.03.012

Author Richards, A. E.
Dalal, R. C.
Schmidt, S.
Title Soil carbon turnover and sequestration in native subtropical tree plantations
Journal name Soil Biology & Biochemistry   Check publisher's open access policy
ISSN 0038-0717
Publication date 2007-08-01
Year available 2007
Sub-type Article (original research)
DOI 10.1016/j.soilbio.2007.03.012
Open Access Status
Volume 39
Issue 8
Start page 2078
End page 2090
Total pages 13
Editor G. Andersson
D. Coleman
J. S. Waid
R. Burns
Place of publication Oxford
Publisher Pergamon-Elsevier Science Ltd
Language eng
Subject C1
300103 Soil Chemistry
770702 Land and water management
Abstract Approximately 30% of global soil organic carbon (SOC) is stored in subtropical and tropical ecosystems but it is being rapidly lost due to continuous deforestation. Tree plantations are advocated as a C sink, however, little is known about rates of C turnover and sequestration into soil organic matter under subtropical and tropical tree plantations. We studied changes in SOC in a chronosequence of hoop pine (Araucaria cwunninghamii) plantations established on former rainforest sites in seasonally dry subtropical Australia. SOC, delta C-13, and light fraction organic C (LF C < 1.6 g cm(-3)) Were determined in plantations, secondary rainforest and pasture. We calculated loss of rainforest SOC after clearing for pasture using an isotope mixing model, and used the decay rate of rainforest-derived C to predict input of hoop pine-derived C into the soil. Total SOC stocks to 100 cm depth were significantly (P < 0.01) higher under rainforest (241 t ha(-1)) and pasture (254 t ha(-1)) compared to hoop pine (176-211 t ha(-1)). We calculated that SOC derived from hoop pine inputs ranged from 32% (25 year plantation) to 61% (63 year plantation) of total SOC in the 0-30 cm soil layer, but below 30 cm all C originated from rainforest. These results were compared to simulations made by the Century soil organic matter model. The Century model Simulations showed that lower C stocks under hoop pine plantations were due to reduced C inputs to the slow turnover C pool, such that this pool only recovers to within 45% of the original rainforest C pool after 63 years. This may indicate differences in soil C stabilization mechanisms under hoop pine plantations compared with rainforest and pasture. These results demonstrate that subtropical hoop pine plantations do not rapidly sequester SOC into long-term storage pools, and that alternative plantation systems may need to be investigated to achieve greater soil C sequestration. (c) 2007 Elsevier Ltd. All rights reserved.
Keyword Soil Science
soil organic carbon
light fraction carbon
Century model
tree plantations
carbon sequestration
Organic-matter Dynamics
Long-term Trends
Land-use Change
Continuous Cultivation
Southern Queensland
Forest Conversion
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

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Created: Tue, 19 Feb 2008, 03:30:59 EST