Evaluating Soil Organic Matter with visible spectroscopy

This study was conducted to develop fundamental relationships between soil organic matter and their visible reflectance spectra. The ultimate goal of this work is to develop a real-time soil property sensor for use in effective farm management. A total of 43 soil samples collected from 0-20 cm depth were used for analysis. Organic matter in soils was analyzed by conventional method in a laboratory. Visible reflectance spectra of the samples were measured by a spectrophotometer in the range of 325 to 1100 nm with a 1 nm increment. Partial least square analysis was used to build prediction models with a calibration data set of 34 randomly chosen samples. The remaining 9 samples were used to validate the models. The prediction models for measured organic matter yielded r2 values of 0.7312. This result could be useful in the development of soil property sensor for site-specific management