A new optical method coupling light polarization and Vis-NIR spectroscopy to improve the measurement of soil carbon content

摘要

Visible and Near-infrared (Vis-NIR) spectroscopy is now a common analytical method to measure different physical and chemical properties of soils, including carbon content. However, prediction model accuracy is insufficient for Vis-NIR spectroscopy to replace routine laboratory analysis. One of the main issues of this technique is facing up to is light scattering due to soil particles. It causes departure in the assumed linear relationship between the absorbance spectrum and the concentration of the chemical components as stated by Beer-Lambert's law, which underpins the linear calibration models.