[Enviro-lunch] Tomorrow 5/3: Teamrat A. Ghezzehei

[Nate Bogie]

[image: Inline image 1]

Hello Everyone,

Please join us for a talk *Tomorrow *by Professor Teamrat A. Ghezzehei,
12-1pm in Room SE2-302.

*Biophysical Model of Soil Aggregation: from root residues to microbial and
physical hotspots*
Professor Teamrat A. Ghezzehei, UC Merced


*Abstract:* Soil aggregation plays important role in storage and movement
of water and essential gases, nutrient cycling, and ultimately supporting
microbial and plant life. Microhabitats within aggregates have been shown
to support the greatest microbial diversity as well. It is one of the most
dynamic and sensitive soil qualities, which readily responds to
disturbances such as cultivation, fire, drought, flooding, and changes in
vegetation. Soil aggregation that is primarily controlled by organic matter
generally exhibits hierarchical organization of soil constituents into
stable units that range in size from a few microns to centimeters. However,
this conceptual model of soil aggregation as the key unifying mechanism
remains poorly quantified and is rarely included in predictive soil models.
Here we introduce a biophysical framework for modeling soil aggregation
from life cycle of individual aggregates to pedon- scale aggregation.
Individual aggregates are treated as hotspots of biological, chemical and
physical processes centered on roots and root residues. At the pedon scale,
soil aggregation is primarily controlled by root architecture and hydration
state. The framework synthesizes current understanding of microbial life in
porous media; water holding and soil binding capacity of biopolymers; and
environmental controls on soil organic matter dynamics. The framework paves
a way for integration of processes that are presently modeled as disparate
or poorly coupled processes, including storage and protection of carbon,
microbial activity, greenhouse gas fluxes, movement and storage of water,
resistance of soils against erosion.

*Bio: *Prof. Teamrat A. Ghezzehei is an Associate Professor of
Environmental Soil Physics at the Life and Environmental Sciences unit at
University of California, Merced. Dr. Ghezzehei was a Postdoctoral Fellow
(2001-2004) and Geological Scientist (2004-2008) at the Earth Sciences
Division, Lawrence Berkeley National Lab. Prior to that Dr. Ghezzehei
received his Ph.D. in Soil Science from Utah State University and B. Sc. in
Soil and Water Conservation from University of Asmara, Eritrea. Prof.
Ghezzehei’s work focuses on physical transformations of soil structure
across scales and the associated biophysical processes, including water and
nutrient dynamics in the rhizosphere and soil aggregation.

When: *April 3 Thursday, 12pm – 1pm*



Where: SE2-302



Coffee will be provided, please bring your own mugs.



We look forward to seeing you,



Nate & Jing



Organizers for Spring 2018: Nate Bogie and Jing Yan

Faculty coordinator: Asmeret Asefaw Berhe
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