EVALUATION OF TOPSOIL IRON OXIDE FROM VISIBLE SPECTROSCOPY

Binny Gopal, Amba Shetty

Abstract: Conventional methods of soil iron oxide estimation are laborious and costly. Reflectance spectroscopy provides a good alternative that may be used to replace conventional methods of soil analysis. Most of the studies are concentrated on near infrared region of the spectrum. But in developing countries like India affording for wider range spectroscopy is a costly affair. Hence this study was conducted to establish relationship between topsoil iron oxide and their visible reflectance spectra in lateritic type of soils. Visible reflectance spectra of the soil samples were measured by a spectroradiometer in the range of 325 to 1100nm with a 1nm increment. Multivariate PLSR method was used to predict iron oxide from reflectance which resulted in moderate prediction of R2 0.71 and 0.62 for calibration and validation respectively. It can be inferred that visible spectroscopy can be effectively used for topsoil iron oxide prediction with an acceptable level of accuracy.

Keywords: Topsoil, iron oxide, visible spectrum, Partial Least Square Regression.

DOI: https://doi.org/10.15623/ijret.2013.0212115