ARS | Publication request: Mapping Soil Electrical Conductivity

Submitted to: Book Chapter
Publication Acceptance Date: July 23, 2004
Publication Date: September 1, 2004
Citation: Sudduth, K.A., Kitchen, N.R. 2004. Mapping Soil Electrical Conductivity. In: Stamatiadis, S., Lynch, J.M., Schepers, J.S. Editors. Remote Sensing For Agriculture And The Environment. Peripheral Editions, Larissa, Greece. P. 188-201.

Technical Abstract: As agricultural producers seek to reduce costs and environmental impacts, they are turning to more information-intensive production methods. When coupled with geographic information system (GIS) and global positioning system (GPS) technologies, sensors can provide the spatially-dense information needed to quantify within-field variations for subsequent management decisions. Apparent soil electrical conductivity (ECa) sensors have shown promise for delineating soil variability, and are in commercial use in many parts of the world. These commercial units either sense ECa remotely from immediately above the soil surface or operate in contact with the soil. They respond to soil differences over a significant part of the soil profile - from 30 cm to well over 1 m, depending on the sensor. Soil ECa is affected by, and can provide a measure of, soil properties such as salinity, texture, cation exchange capacity (CEC), and moisture content. Since ECa integrates texture and moisture availability, two soil characteristics that affect productivity, it can also aid in interpreting spatial yield variations. The relationship of ECa to crop yield is often more pronounced in conditions of water stress, and ECa has explained over 50 percent of the within-field yield variation in some such cases. Other uses of ECa data have included refining the boundaries of soil survey map units, estimating herbicide leaching potential, and creating sub-field management zones. The reliability and applicability of ECa data can be maximized through proper sensor selection and operation and through the choice of appropriate data analysis methods. Simultaneous collection and analysis of other sensor-acquired data such as elevation can also increase the utility of the ECa information. Soil ECa mapping is an effective and efficient data collection tool for precision agriculture.