f SIMULTANEOUS PROXIMAL SENSING OF SOIL PHYSICAL, CHEMICAL, AND BIOLOGICAL PROPERTIES

Soil electrical conductivity (EC) sensing can rapidly delineate areas of contrasting soil properties within agricultural fields. Unless the signal is responding to a dominant soil property such as salinity or claypan, calibrating the signal in farm fields to specific properties has proven difficult. As a result, while the practice of soil EC mapping is receiving widespread acceptance in commercial agriculture, it is being adopted primarily as a soil pattern delineator. Recent advancements in proximal soil sensing allow for the mapping of soil properties such as organic matter using an optical sensor, and pH using an electrochemical sensor, along with soil EC. Also, elevation data from GPS receivers can provide co-located information about the topography of the field. When fields are mapped with all these sensors mounted on one platform, and calibration soil sample data are available, multivariate analysis techniques can be applied to calibrate the sensor readings to specific soil properties. Results from a multi-field, multi-state study show effective calibrations can be accomplished to a variety of soil properties using this sensorfusion approach.