Application of Vis-NIR spectroscopy for determination the content of organic matter in saline-alkali soils

Yuling Ba; Jinbao Liu; Jichang Han; Xingchang Zhang

doi:10.1016/j.saa.2019.117863

Application of Vis-NIR spectroscopy for determination the content of organic matter in saline-alkali soils

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 15:229:117863. doi: 10.1016/j.saa.2019.117863. Epub 2019 Nov 26.

Authors

Yuling Ba¹, Jinbao Liu², Jichang Han³, Xingchang Zhang⁴

Affiliations

¹ College of Resource and Environment, Northwest A&F University, Yangling 712100, China; Shaanxi Provincial Land Engineering Construction Group Co., Ltd., Xi'an, Shaanxi 710075, China.
² Shaanxi Provincial Land Engineering Construction Group Co., Ltd., Xi'an, Shaanxi 710075, China; Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology, Xi'an 710048, China; Key Laboratory of Degraded and Unused Land Consolidation Engineering, The Ministry of Natural Resources, Xi'an, Shaanxi 710075, China. Electronic address: jinbaoliu@xaut.edu.cn.
³ Shaanxi Provincial Land Engineering Construction Group Co., Ltd., Xi'an, Shaanxi 710075, China; Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology, Xi'an 710048, China; Key Laboratory of Degraded and Unused Land Consolidation Engineering, The Ministry of Natural Resources, Xi'an, Shaanxi 710075, China.
⁴ College of Resource and Environment, Northwest A&F University, Yangling 712100, China.

PMID: 31806478
DOI: 10.1016/j.saa.2019.117863

Abstract

Visible and near-infrared diffuse reflectance spectroscopy (Vis-NIR) has been recognized as a fast method to evaluate the content of soil organic matter (SOM) in various types of soil. The accuracy of Vis-NIR is comparable to conventional laboratory methods for estimating SOM. However, very few studies have applied Vis-NIR to estimate SOM in saline-alkali soil. This study aimed to investigate the efficiency of spectral data for evaluating SOM in saline-alkali soil. Soil samples (n = 291) were collected from the five major saline-alkali soil regions in Shaanxi. SOM was measured using standard methods and the samples were scanned using ASD Fieldspec4 at wavelength of 350-2500 nm to obtain spectral data. Twenty-six pre-processing methods were tested and partial least squares regression (PLSR) was used to estimate SOM. The best preprocessing was R + SG + SNV + FD. The calibration results were Pc = 15, Rc² = 0.92, RMSEC = 1.11, SEC = 1.12, Slope = 0.92, Offset = 0.45; the validation results were Rv² = 0.97, RPD = 5.21, RMSEP = 0.38, SEP = 0.38, Slope = 0.97, Offset = 0.17. Therefore, this main objective of the study was to propose an effective approach based on Vis-NIR spectroscopy and Chemometrics for predicting saline-alkali SOM contents in the center of Shaanxi, China.

Keywords: Chemometrics; Partial least squares regression; SOM; Saline-alkali soil; Vis-NIR spectroscopy.