Mid-infrared spectroscopy for the estimation of some soil properties

Abstract

Techniques such as mid-infrared (MIR) spectroscopy can be used to identify the classes and properties of soils with high preci-sion. In the present study, 312 soil samples of different orders, representative of Colombian agricultural zones, were studied, among which are found Inceptisols and Verisols of the Sinú valley (Córdoba), Andisols of the Eastern Andes Mountain range (Cundinamarca), and Oxisols of the Eastern plains of Colombian (Meta), with the aim of evaluating the ability of mid-infrared spectroscopy to estimate soil properties such as organic carbon, Ca, Mg, Na, K, P, Al, and pH. The results obtained through the analysis of the curves allowed observing that the greatest number of properties are reflected in the spectral region be-tween 400 and 850 cm-1. The Inceptisols and Vertisols gave the best results in the calibration of the models for the majority of the properties, followed by the Andisols and finally the Oxisols, which did not show good results. In the descriptive analysis, the observed values showed a behavior similar to the values predicted from the models, for those properties with representa-tive spectral models. The majority of the properties did not show a normal distribution, and the coefficients of variation were very high.