[Enviro-lunch] (Enviro-Lunch) Enviro-lunch (8/24): Teamrat A. Ghezzehei, "Life cycle of soil aggregates: from root residue to microbial and physical hotspots"

[Lixia Jin]

[cid:BF51CB48-9860-47D8-9C55-A65B53240779 at ucmerced.edu]
Dear all,
Please support our community in Earth and environmental sciences by attending our weekly events. First speaker in our Enviro-lunch brown bag seminar series will be:

Teamrat A. Ghezzehei
Associate Professor, Environmental Systems
Life cycle of soil aggregates: from root residue to microbial and physical hotspots

Abstract: Soil aggregation is a physical state of soil in which clumps of primary soil particles are held together by biological and/or chemical cementing agents. Aggregations plays important role in storage and movement of water and essential gases, nutrient cycling, and ultimately supporting microbial and plant life. It is also 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 provide a biophysical framework for quantitative and predictive modeling of soil aggregation and its attendant soil characteristics. The framework treats aggregates as hotspots of biological, chemical and physical processes centered around roots and root residue. We keep track of the life cycle of an individual aggregate from it genesis in the rhizosphere, fueled by rhizodeposition and mediated by vigorous microbial activity, until its disappearance when the root-derived resources are depleted. 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.

When: Aug. 24th, Thursday, 12pm – 1pm
Where: SE2-302
Speakers need to arrive the seminar room 10 minutes prior to presentations.
If speakers would prefer to use laser pointer/slide advancing remote, please bring your own.

Coffee will be provided and please bring your own mugs.
We look forward to seeing you,

Organizers for 2017-18: Nathaniel Bogie and Lixia Jin
Faculty coordinator: Asmeret Asefaw Berhe
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ucmerced.edu/pipermail/enviro-lunch/attachments/20170817/94508fd4/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: PastedGraphic-1.png
Type: image/png
Size: 25186 bytes
Desc: PastedGraphic-1.png
URL: <http://lists.ucmerced.edu/pipermail/enviro-lunch/attachments/20170817/94508fd4/attachment-0001.png>