Soil, Water and Environmental Science & School of Earth and Environmental Sciences Seminar Jan 30

Jan 30 2012 - 3:00pm - 4:00pm

Defining and quantifying soil organic matter stability


Alain F. Plante
Assistant professor, soil biogeochemistry
Dept. Earth and Environmental Science
University of Pennsylvania


Part of our conceptualization of SOM stability has been inherited from studies of above-ground litter decomposition. However, the concept must go beyond biochemical composition and encompasses all mechanisms that act to stabilize organic matter in soil. As such, Schmidt et al (2011) propose SOM stability as an ecosystem property rather than a chemical property. The ambiguity of what comprises SOM stability is reflected in the wide range of approaches used to measure or quantify it. Various physical, chemical and biological fractionation techniques as well as analytical and instrumental chemical techniques have been used to characterize SOM quality to varying degrees, though correlations between various methods are not frequently reported or apparent. While SOM stability may not be a singular property, its implications in the dynamics of SOM make it important to express in a quantitative manner, likely through the use of indices. Our ability to predict SOM responses to climate change and other disturbances will be greatly improved when models adequately incorporate quantitative and measurable expressions of SOM stability. This demand is now decades old, but remains a significant challenge.




Marley Building Room 230 Refreshments at 2:40 PM outside Marley 230
Contact name: 
Kristie Gallardo
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