Using the EM38 and VisNIR Spectroscopy to Map Soil Series Across a Landscape.

Spatial variability of soils across a landscape makes mapping soil series costly and time consuming. Spectroscopy has been proven to predict soil properties in the lab, yet few studies have evaluated spectroscopy’s predictability in the field.  This study was conducted to determine if visible near infrared diffuse reflectance spectroscopy (VNIR-DRS) along with electrical conductivity readings from the EM38 can be used in the field to create 3D maps of soil series. If successful, EM38 and VNIR-DRS would provide a means to rapidly and inexpensively map the soil series across a landscape. After scanning three fields in central Texas with the EM38 and collecting elevation data, sixteen soil cores were collected from each field.  Spectral data, inorganic carbon, total carbon, and particle size distribution was collected for all 48 cores. The data from these 48 cores and cores previously scanned by our lab will be used to create calibration models to predict the properties of these soils. These properties will be used to create 3D maps of the soils in these fields. Collected data and future results will be presented at the ASA meeting in November 2009.