The Application of Infrared Spectroscopy as A Rapid and Innovative Technology for Soil Quality Properties Prediction

Abstract

A major function of soil is to provide fundamental natural resources for the survival of plants, animals, and the human race. The maintenance of soil quality is critical for ensuring the sustainability of the environment and it depends on the balances of soil structure and nutrient composition. To determine soil quality, several methods were already widely used in which most of them were based on solvent extraction followed by other laboratory procedures. However, these methods often require laborious and complicated processing for samples. Infrared reflectance spectroscopy can be considered as a rapid, innovative and nondestructive method for determining soil properties. The objective of this study is to apply infrared technology in classifying soils based on their land-use and to predict related soil quality properties based on its infrared reflectance. Soil infrared spectrum was acquired in the wavelength range from 1000 to 2500 nm for ricefield (with a total of 30 points) and ground-field soils (31 points). Principal component analysis (PCA) with non-iterative partial least square (NIPALS) was applied to analyze soils spectral data. The result showed that two principal components (PC1=97% ad PC2 = 3%) based on infrared reflectance data were successfully able to recognize and distinguish soils based on their landuse. Furthermore, the wavelength ranges of 950-1128 were related to soil nitrogen content whilst 1460 nm and 1920 nm were associated with soil moisture content. Soil organic matter can be predicted in the wavelength range of 1230-1315 nm, 1580-1680 nm, and 2095-2200 nm. This may conclude that infrared technology was feasible to use as a rapid, innovative and non-destructive method in soils quality properties classification and evaluation.