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Microbial competition as a driving force of primed soil organic matter decomposition

EU MICROSOM

From 02/2007 to 01/2009

Principal Investigator: Yakov Kuzyakov

Priming effects (PE) are strong, generally short-term changes in the turnover of native soil organic matter (SOM) induced by comparatively moderate treatments of the soil. Given the current concerns over global warming, it is important to understand when soils serve either as a source or sink for atmospheric CO2. Prediction and modeling SOM dynamics requires the identification of the physiological and environmental constraints driving microbial activities. Therefore the multidisciplinary outlook including at least soil chemistry, microbial physiology and ecology so as ecological modeling is necessary for successful study of the mechanisms of priming effects. The aim of this project is the elucidation of the mechanisms of restoration – mineralization of soil organic matter based on interdisciplinary research strategy leading to a predictive understanding of the priming effects. specific goals of the project: to monitor the growth kinetic of soil microbial communities during succession decomposing the organic substrates of high and low availability; to determine the enzymatic activities of soil microbial community at different stages of succession in relation to nutrient availability and energetic status; to relate both the growth strategies and the enzymatic activities of soil microorganisms decomposing organic substrates to the extra CO2 evolved from soil; to study the environmental factors (biotic and abiotic) controlling the intensity of the competition for substrate between r-strategists with rapid growth rates and K-strategists with slow growth rates; to investigate the impact of the chemical characteristics of substrate (C/N ratio, polymerization) and soil nutrient content on the intensity of priming effect; to investigate the impact of the temporal course of FOM incorporation to soil on the intensity of priming effect; to develop the process oriented model, which simulates the different scenarios of priming effect basing on experimental data.

Homepage: http://www.aec.uni-bayreuth.de/MICROSOM_3.pdf

last modified 2008-12-17