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Grad student seminar: Linking soil organic matter composition to soil physical & chemical properties

Thursday, April 23, 2020, 12:30PM - 1:30PM

Speaker

Maggie Bowman

Location:

Virtual seminar

Contact Jessie for Zoom link

Please join us this Thursday for our INSTAAR Grad seminar as we go virtual!

Full title

Linking soil organic matter composition to soil physical and chemical properties across a diverse set of soils: A multi method approach

Abstract

Soils contain the largest pool of terrestrial organic carbon and the organic content of soil is strongly influenced by climate, vegetation, land use, and physicochemical properties of the soil. In order to better understand factors that control soil carbon, I seek to understand the mechanisms of stabilization of soil organic matter (SOM) across a diverse range of soil types. To integrate SOM stabilization and vulnerability across different spatial scales, it is important to understand the mechanisms of stabilization and how broad (climate) and fine scale (soil physicochemical properties) impact SOM dynamics under changing temperature anf moisture conditions. The goals of my research are to (1) develop fluorescence spectroscopy models designed for SOM; (2) understand how the molecular composition of SOM varies as a function of fine and broad scale controls; and (3) link composition and mechanisms of stability for SOM across diverse soil types. Using fluorescence spectroscopy and Parallel Factor Analysis (PARAFAC) I created a universal 6 component soil model to compare and interpret fluorescence signals. Using sequential extraction methods, I can determine the composition of the SOM that is hydraulically active (labile non-stabilized) and which fraction is more tightly held in the soils (stabilized). To understand how the molecular composition of SOM varies across a diverse range of soil types, I will be coupling fluorescence spectroscopy and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) of soil extracts. Combining environmental factors, physicochemical properties of the soil, fluorescence spectroscopy, FT-ICR-MS data, and climate change incubation data I will determine which factors influence SOM composition in both the hydraulically active and stable fractions and gain insight into the interplay between mineralogy, SOM composition, stabilization and vulnerability to changes in broad scale controls.