Fatemeh Mousavi - Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
Ehsan abdi - Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran,
babak Shahbodagh - School of Civil and Environmental Engineering, UNSW Australia, Sydney, ۲۰۵۲ Australia
Mohammad Vahab - School of Civil and Environmental Engineering, UNSW Australia, Sydney, ۲۰۵۲ Australia,

The quality of soil is very important for construction of forest roads. It is essential to determine the soil characteristics prior to any road construction. One of the most important factors affecting the soil volume change is its clay content. Conventional methods used for determination of the soil clay content are often expensive, slow and destructive to the environment. VisNIR (۳۵۰-۲۵۰۰ nm) diffuse reflectance spectroscopy is a cheap, non-destructive and rapid method to estimate soil clay content with less damage to the environment. The objective of this study is to determine the prediction accuracy of visNIR. ۴۵ soil samples from Namkhaneh district in the educational and experimental forest of the University of Tehran were collected for this study. The VisNIR spectra of soil samples were used to predict the clay content of soil using the partial least squares (PLS) regression. The calibration quality was evaluated by calibration R۲ and RMSE. The results show a strong relationship between reflectance spectral and clay content using the PLS method.

VisNIR, reflectance spectroscopy, non-destructive, PLS.