TY - JOUR
T1 - Temperature sensitivity of soil organic matter decomposition-what do we know?
AU - von Lützow, Margit
AU - Kögel-Knabner, Ingrid
N1 - Funding Information:
Acknowledgements We thank the two reviewers as well as the editor for their constructive and very helpful advice. This study was financially supported by the Federal Ministry of Education and Research within the project ‘Potential analysis of modifications of land use systems and their biogeochemical cycles for the attainment of the greenhouse gas reduction goals’ (FKZ 01LG0801A).
PY - 2009/11
Y1 - 2009/11
N2 - Soil organic matter (SOM) represents one of the largest reservoirs of carbon on the global scale. Thus, the temperature sensitivity of bulk SOM and of different SOM fractions is a key factor determining the response of the terrestrial carbon balance to climatic warming. We condense the available knowledge about the potential temperature sensitivity and the actual temperature sensitivity of decomposition in situ, which ultimately depends on substrate availability. We review and evaluate contradictory results of estimates of the temperature sensitivity of bulk SOM and of different SOM fractions. The contradictory results demonstrate a need to focus research on biological and physicochemical controls of SOM stabilisation and destabilisation processes as a basis for understanding strictly causal relationships and kinetic properties of key processes that determine pool sizes and turnover rates of functional SOM pools. The current understanding is that temperature sensitivity of SOM mineralisation is governed by the following factors: (1) the stability of SOM, (2) the substrate availability, which is determined by the balance between input of organic matter, stabilisation and mineralisation of SOM, (3) the physiology of the soil microflora, its efficiency in substrate utilisation and its temperature optima and (4) physicochemical controls of destabilisation and stabilisation processes, like pH and limitation of water, oxygen and nutrient supply. As soil microflora is functionally omnipotent and most SOM is of high age and stability, the temperature dependence of stable SOM pools is the central question that determines C stocks and stock changes under global warming.
AB - Soil organic matter (SOM) represents one of the largest reservoirs of carbon on the global scale. Thus, the temperature sensitivity of bulk SOM and of different SOM fractions is a key factor determining the response of the terrestrial carbon balance to climatic warming. We condense the available knowledge about the potential temperature sensitivity and the actual temperature sensitivity of decomposition in situ, which ultimately depends on substrate availability. We review and evaluate contradictory results of estimates of the temperature sensitivity of bulk SOM and of different SOM fractions. The contradictory results demonstrate a need to focus research on biological and physicochemical controls of SOM stabilisation and destabilisation processes as a basis for understanding strictly causal relationships and kinetic properties of key processes that determine pool sizes and turnover rates of functional SOM pools. The current understanding is that temperature sensitivity of SOM mineralisation is governed by the following factors: (1) the stability of SOM, (2) the substrate availability, which is determined by the balance between input of organic matter, stabilisation and mineralisation of SOM, (3) the physiology of the soil microflora, its efficiency in substrate utilisation and its temperature optima and (4) physicochemical controls of destabilisation and stabilisation processes, like pH and limitation of water, oxygen and nutrient supply. As soil microflora is functionally omnipotent and most SOM is of high age and stability, the temperature dependence of stable SOM pools is the central question that determines C stocks and stock changes under global warming.
KW - Arrhenius equation
KW - CO flux
KW - Michaelis-Menten kinetics
KW - Q10
KW - SOM destabilisation
KW - Temperature sensitivity
UR - http://www.scopus.com/inward/record.url?scp=70350430050&partnerID=8YFLogxK
U2 - 10.1007/s00374-009-0413-8
DO - 10.1007/s00374-009-0413-8
M3 - Review article
AN - SCOPUS:70350430050
SN - 0178-2762
VL - 46
SP - 1
EP - 15
JO - Biology and Fertility of Soils
JF - Biology and Fertility of Soils
IS - 1
ER -