HR: 14:00h
AN: NS43A-01 INVITED     [Abstracts]
TI: Mapping Soil Properties for Ecohydrological Studies in Small Semi-Arid Watersheds using Electromagnetic Induction
AU: Robinson, D A
EM: darob@stanford.edu
AF: Stanford University, Dept of Geophysics 397 Panama Mall, Stanford, CA 94305, United States
AU: * Jones, S B
EM: scott.jones@usu.edu
AF: Utah State University, Dept of Plants, Soils and Biometerology Ag Sci Building, Logan, UT 84322, United States
AB: While traditional methods of soil mapping provide a qualitative description of soil properties across a landscape they fail to provide spatially detailed quantitative data needed in ecohydrological studies. Electromagnetic induction (EMI) mapping is a useful tool for mapping soil properties where the penetration depth of a handheld sensor is just over a meter when carried 0.2 m above the soil surface, and the measurement integrates over a volume of several cubic meters, similar to the scale of a soil pedon. Our recent research efforts have focused on mapping soil properties in a semi-arid watershed at Reynolds Creek, ID, using geophysical methods with the idea of complimenting point-measured data using distributed sensors. In the Reynolds Creek environment the stream flow response is controlled largely by the subsurface and hence the identification of soil hydrological properties and the delineation of soil boundaries is important for modeling the watershed hydrology. Data collected using electromagnetic induction provide spatially informative maps tied to the subsurface bulk electrical conductivity (EC). The utility of bulk EC measurements for delineating soils stems from measured sensitivity to the physical and biogeochemical properties. Instrument output tends to increase in soils with more 2:1 clay, higher water content and higher solute concentration. Therefore, maps of bulk electrical conductivity are good for differentiating between coarse and fine textured soils and for identifying hydrological flow pathways. Preliminary data suggest EMI maps can be correlated to provide detailed spatial information of soil texture, water content, hydraulic conductivity and hydrological flow pathways in catchment hydrology, potentially improving hydrological model parameter estimation.
DE: 1813 Eco-hydrology
DE: 1865 Soils (0486)
DE: 1866 Soil moisture
DE: 1895 Instruments and techniques: monitoring
SC: Near-Surface Geophysics [NS]
MN: 2007 Joint Assembly