Impact of tropical land-use change on soil organic carbon stocks - a meta-analysis

Land-use changes are the second largest source of human-induced greenhouse gas emission, mainly due to deforestation in the tropics and subtropics. CO₂ emissions result from biomass and soil organic carbon (SOC) losses and may be offset with afforestation programs. However, the effect of land-use ch...

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Bibliographic Details
Published in:	Global change biology Vol. 17; no. 4; pp. 1658 - 1670
Main Authors:	DON, AXEL, SCHUMACHER, JENS, FREIBAUER, ANNETTE
Format:	Journal Article
Language:	English
Published:	Oxford, UK Blackwell Publishing Ltd 01.04.2011 Wiley-Blackwell Wiley
Subjects:	Afforestation Agricultural land Animal and plant ecology Animal, plant and microbial ecology Biological and medical sciences biomass bulk density carbon dioxide Carbon dioxide emissions Carbon sequestration carbon sinks cropland crops Deforestation fallow Farm buildings Fundamental and applied biological sciences. Psychology General aspects Grasslands greenhouse gas emissions Greenhouse gases Land use land use change Meta-analysis Organic carbon primary forests secondary forests Soil density soil organic carbon Soil sciences Soil surfaces Soils subsoil Subsoils subtropics Terrestrial ecosystems Tropical environments tropics Bulk density Deforestation Organic carbon Tropical zone land-use change soil organic carbon Afforestation Land use Metaanalysis Soils tropics Subsoil Stock Life Sciences
ISSN:	1354-1013, 1365-2486
Online Access:	Get full text
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Summary:	Land-use changes are the second largest source of human-induced greenhouse gas emission, mainly due to deforestation in the tropics and subtropics. CO₂ emissions result from biomass and soil organic carbon (SOC) losses and may be offset with afforestation programs. However, the effect of land-use changes on SOC is poorly quantified due to insufficient data quality (only SOC concentrations and no SOC stocks, shallow sampling depth) and representativeness. In a global meta-analysis, 385 studies on land-use change in the tropics were explored to estimate the SOC stock changes for all major land-use change types. The highest SOC losses were caused by conversion of primary forest into cropland (−25%) and perennial crops (−30%) but forest conversion into grassland also reduced SOC stocks by 12%. Secondary forests stored less SOC than primary forests (−9%) underlining the importance of primary forests for C stores. SOC losses are partly reversible if agricultural land is afforested (+29%) or under cropland fallow (+32%) and with cropland conversion into grassland (+26%). Data on soil bulk density are critical in order to estimate SOC stock changes because (i) the bulk density changes with land-use and needs to be accounted for when calculating SOC stocks and (ii) soil sample mass has to be corrected for bulk density changes in order to compare land-use types on the same basis of soil mass. Without soil mass correction, land-use change effects would have been underestimated by 28%. Land-use change impact on SOC was not restricted to the surface soil, but relative changes were equally high in the subsoil, stressing the importance of sufficiently deep sampling.
Bibliography:	http://dx.doi.org/10.1111/j.1365-2486.2010.02336.x ArticleID:GCB2336 ark:/67375/WNG-NPKRDCS7-1 istex:10C79D2BEC5E4F1E85695082777DDFB37E8CFA97 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 ObjectType-Article-1 ObjectType-Feature-2 content type line 23
ISSN:	1354-1013 1365-2486
DOI:	10.1111/j.1365-2486.2010.02336.x