Soil Conductivity Sensing on Claypan Soils: Comparison of Electromagnetic Induction and Direct Methods

SOIL CONDUCTIVITY SENSING ON CLAYPAN SOILS: COMPARISON OF ELECTROMAGNETIC INDUCTION AND DIRECT METHODS*

	K. A. Sudduth	N. R. Kitchen	S. T. Drummond
	USDA-Agricultural Research Service Cropping Systems and Water Quality Research		Bio & Ag Engineering Univ. of Missouri
Columbia, Missouri, USA

ABSTRACT

Soil electrical conductivity (EC) sensing provides a means for rapidly mapping variations in soil properties such as salinity, moisture, and clay content. On claypan soils, EC measurements are related to topsoil depth above the claypan horizon, an important factor in spatial crop productivity differences on these soils. Soil EC data obtained with a noncontact sensor based on electromagnetic induction principles were compared with data from a direct contact, coulter-based sensor. Differences in EC readings were attributed to differences in sensing depth between the sensors and operating modes. The electromagnetic induction sensor generally provided better estimates of topsoil depth and correlations to crop productivity over the full range of topsoil depths encountered (up to 150 cm). However, the coulter-based sensor performed well at shallower topsoil depths (up to 90 cm), and would also be useful for investigating soil differences in precision agriculture practice.

*Presented at the 4th International Conference on Precision Agriculture
St. Paul, Minnesota, 19-22 July 1998.

To view the entire document, click the PDF button on the left.

Research Publications