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Title: LANDSCAPE-SCALE CHARCTERIZATION OF SPATIAL VARIABILITY USING GEOSPATIAL ECA MEASUREMENTS

Author
item Corwin, Dennis
item LESCH, SCOTT - UC RIVERSIDE, CA.

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2004
Publication Date: 10/31/2004
Citation: Corwin, D.L., Lesch, S.M. 2004. Landscape-scale charcterization of spatial variability using geospatial eca measurements. Soil Science Society of America. Paper No. 4038.

Interpretive Summary:

Technical Abstract: Characterizing spatial variability is an important consideration of any landscape-scale soil-related problem. Geospatial measurements of apparent soil electrical conductivity (ECa) are useful for characterizing spatial variability by directing soil sampling. The objective of this presentation is to discuss equipment, protocols, sampling designs, and precautions for conducting an ECa survey to characterize spatial variability. To demonstrate its flexibility, data will be presented for applications including modeling of NPS pollutants in the vadose zone, precision agriculture, and soil quality assessment. In particular, a preliminary spatio-temporal study of changes in soil quality will be demonstrated for a drainage water reuse study site. The spatio-temporal study used electromagnetic induction ECa data and a response-surface sampling design to select 40 sites that reflected the spatial variability of a saline-sodic field in California's San Joaquin Valley. Soil samples were collected in August 1999 and April 2002. Data from 1999 indicated high levels of salinity, which increased with depth, high levels of SAR, which also increased with depth, and moderate to high levels of B and Mo. The application of drainage water for 32 months leached the surface 0.3-0.6 m of soil. Preliminary spatio-temporal analyses indicate at least short-term feasibility of drainage water reuse from the perspective of soil quality when the goal is forage production for grazing livestock.