The main goal of this study is to discover the iron oxide content in soil using Vis-NIR spectroscopy with the help of ASD FieldSpec4 instrument. Estimation of iron Oxide content can be utilized as an indicator for soil fertility. The instrument ASD FieldSpec4 Spectroradiometer is utilized for capturing spectral signature of gathered soil samples from various areas in Jalna district of Maharashtra state in India. In the Vis-NIR wavelength range we utilized Partial Least Squares Regression (PLSR) method to estimate the iron oxide content present in the samples of soil. Also few pre-processing methods were applied such as savitzky golay and first derivative preprocessing. The outcomes were assessed by root mean square error (RMSE) and coefficients of determination (R2). The observations with the help of PLSR models with the first derivative pre-processing was (RMSE =0.008711, R2 =0.91 for calibration and RMSE= 0.001624, R2=0.92 for validation) and with savitzky golay pre-processing was (RMSE =0.004415, R2 =0.87 for calibration and RMSE=0.004209, R2=0.89 for validation). It is inferred that, 444nm, 480nm, 529nm, 680nm, 880nm and 920nm wavelength bands are sensitive to soil iron oxide. Taking everything into account, concentrations of iron oxide in soils could be surveyed by soil spectra; therefore, spectral reflectance would be an elective tool for monitoring soil metals.

Iron oxide content, ASD fieldspec4 spectroradiometer, PLSR, Vis-NIR

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