Methods to quantify biogeochemical changes in the vadose zone David J. Hansena, Jennifer T. McGuirea

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Methods to quantify biogeochemical changes in the
vadose zoneDavid J. Hansena, Jennifer T.
McGuirea, Binayak P. MohantybaDepartment of
Geology and Geophysics, Texas AM University,
College Station, TXbDepartment of Biological and
Agricultural Engineering, Texas AM University,
College Station, TX
Anatomy of an experiment
Possible Results
Tensiometer

• The interfaces between soil structures will be
  hotspots of biogeochemical activity.
• The magnitude of biogeochemical changes at the
  interfaces may be more important than the those
  occurring in the bulk soil.
• Development of quantifiable redox zonation at
  soil structures.

Rainfall simulator
Platinum electrode
Future Work
TDR
Lysimeter
24 hrs
Datalogger sampling setup (Measures tensiometers,
TDR, and Pt Electrodes)

• Creation of a capillary fringe by adding a water
  table at the bottom of the columns.
• Using a killed control column to understand
  the role of microbial activity verses geochemical
  changes.
• Improvement/development of a coupled unsaturated
  hydrological and biogeochemical model (HP1) using
  data obtained from experiments.

Automated valve controller
Automated fraction collector
YSI probe
- Indicates sampling interval time
Why each analysis is important
Acknowledgements

• Funding made possible by the National Science
  Foundation Hydrological Sciences
• Jami Hansen, Erik Smith, Tara Kneeshaw, Susan
  Baez Cazull, Bhavna Arora