89 Quantifying and Modeling Soil Structure Dynamics

Oral Session
S01 Soil Physics
Soil structure is important in the air-soil-water continuum for air- and water- exchange, transport of chemicals and micro-organisms, and root growth. Macro-scale soil structure consists of interpedal porosity, shrinkage fractures, and biochannels; whereas micro-scale soil structure depends more on clay mineralogy, properties of soil organic matter, and microbial activity. These components of soil structure change in response to soil water content, bio-activity, and applied external load. Soil structure not only varies across scales but often within the vertical profile. Although in the past soil had been considered homogeneous, soil structure is now often considered directly or indirectly in models of water flow and solute transport, and of root growth. In most cases, the soil structural aspects are considered a static model input. The objective of this session is to explore ways of describe dynamic aspects of soil structure and incorporate this knowledge into models of the whole system. Knowledge gaps will be delineated and techniques proposed to understand, synthesize, and quantify these gaps.
Monday, November 2, 2009: 12:55 PM-2:45 PM
Convention Center, Room 411, Fourth Floor

Presidings:
Sally Logsdon and Rainer Horn
Organizers:
Teamrat Ghezzehei , Sally Logsdon , Rainer Horn and Markus Berli
12:55 PM
Introductory Remarks
1:00 PM
Quantifying Physical Properties That Underlie Soil Structure Dynamics: Case Studies On the Impacts of Roots and Biota.
Paul Hallett, Scottish Crop Res. Inst.; Pierre Barre, INRA Grignon; Sonja Schmidt, Scottish Crop Res. Inst.; Shuichiro Yoshida, Natl. Agriculture and Food Res. Organization; Bin Zhang, Inst. of Soil Sci., Chinese Academy of Sciences
1:20 PM
1:40 PM
Incorporating Physicochemical Protection by the Soil Matrix Into Biogeochemical Models.
Johan Six, Univ. of California, Davis; Steven DE Gryze, Univ. of California, Davis; Fugen Dou, Univ. of California, Davis; Keith Paustian, Colorado State Univ.; Gabe Olchin, Colorado State Univ.; Mac Post, Oak Ridge National Lab.
2:00 PM
Dynamics of Soil Pore Networks Investigated by X-Ray Microtomography.
Stephan Peth, Christian-Albrechts-Univ.; Jens Nellesen, Univ. of Dortmund; Felix Beckmann, GKSS Res. Centre; Rainer Horn, Christian-Albrechts-Univ.
2:15 PM
Excluded-Volume Expansions of Archie's Law for Gas and Solute Diffusivities and Electrical and Thermal Conductivities in Variably-Saturated Porous Media.
Shoichiro Hamamoto, Saitama Univ.; Per Moldrup, Aalborg Univ.; Ken Kawamoto, JAPAN, Saitama Univ.; Toshiko Komatsu, Saitama Univ.
2:30 PM
Multifractal Characterization of Soil Pore Shapes in Aggregates.
Daniel Gimenez, Rutgers State Univ.; Adolfo Posadas Durand, Intl. Potato Center and CNPDIA/EMBRAPA; Thais L. Ohashi, Universidade Federal de São Carlos
2:45 PM
Adjourn
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