Measurements of soil properties by cation-exchange capacity (CEC) and X-Ray diffraction (XRD) are often time consuming and expensive processes. Near-infrared reflectance (NIR) spectroscopy can be used to create calibration models based on CEC values and XRD mineralogy. These calibrations can then be utilized to predict both cation exchange capacities and mineral composition of soil samples in near real-time without the need for additional costly and time consuming laboratory measurements. NIR has the added benefits of providing a field portable, non-destructive sample measurement. Multiple soil properties can also be simultaneously predicted via a single spectrum. Quantitative calibrations for NIR analyzers are developed using statistical methods that relate measured NIR reflectance to the material properties of interest. This poster examines the quantitative determination of soil mineralogy based on XRD determined kaolinite, montmorillonite and mica abundances, and swelling clays determination by CEC measurement with multivariate calibrations using NIR spectroscopy.
