HR: 13:40h
AN: H43I-01    [Abstracts]
TI: Exploring Soils and Ecohydrological Structure in Small 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: Abdu, H
EM: hiruyabdu@cc.usu.edu
AF: Utah State University, Dept of Plants Soils and Climate Ag Sci Building, Logan, UT 84322, United States
AU: Jones, S B
EM: scott.jones@usu.edu
AF: Utah State University, Dept of Plants Soils and Climate Ag Sci Building, Logan, UT 84322, United States
AU: Seyfried, M S
EM: mseyfrie@nwrc.ars.usda.gov
AF: USDA-ARS, 800 Park Blvd, Boise, ID 83712, United States
AU: Lebron, I
EM: lebron@stanford.edu
AF: Stanford University, Dept of Geophysics 397 Panama Mall, Stanford, CA 94305, United States
AU: Knight, R
EM: rknight@pangea.stanford.edu
AF: Stanford University, Dept of Geophysics 397 Panama Mall, Stanford, CA 94305, United States
AB: Soils, through their control over resources in drylands play a fundamental, but often unquantified role in determining the structure, function and diversity of these terrestrial ecosystems. There is an important ecological need for quantitative subsurface data, spatially distributed, that links soils, water, and plant community structure. Pressing ecohydrological questions in the Western US include the contribution of subsurface properties and processes to forest die back, in such species as pinyon pine and quaking aspen. The role of soil resources, nutrients or soil moisture is not fully understood. Soil texture patterns and the location of subsurface flow paths undoubtedly contribute to plant community structure. Understanding the soil-water-vegetation links within the ecosystem are important for understanding plant community emergent behavior and structure. We demonstrate the use of electromagnetic induction (EMI) for mapping a small watershed (41 ha) at the Reynolds Creek experimental watershed in Idaho. EMI mapping, compared to auguring soil cores, increases the number of soil measurements across a watershed that can be obtained by about 3 orders of magnitude, from 15 cores per day to perhaps 15,000 EMI measurements per day. The EMI map is highly correlated with the soil texture and illuminates the location of flow paths and subsurface colluvium accumulation zones. Vegetation community mapping combined with EMI mapping allows the identification of plant community niches within the watershed as related to subsurface properties. The information obtained, and the insight gained, helps us to understand how subsurface processes contribute to ecohydrological structure in drylands.
DE: 1831 Groundwater quality
DE: 1835 Hydrogeophysics
DE: 1865 Soils (0486)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2007 Fall Meeting