Dataset Information

Desert soil clay content estimation using reflectance spectroscopy preprocessed by fractional derivative.

ABSTRACT: Effective pretreatment of spectral reflectance is vital to model accuracy in soil parameter estimation. However, the classic integer derivative has some disadvantages, including spectral information loss and the introduction of high-frequency noise. In this paper, the fractional order derivative algorithm was applied to the pretreatment and partial least squares regression (PLSR) was used to assess the clay content of desert soils. Overall, 103 soil samples were collected from the Ebinur Lake basin in the Xinjiang Uighur Autonomous Region of China, and used as data sets for calibration and validation. Following laboratory measurements of spectral reflectance and clay content, the raw spectral reflectance and absorbance data were treated using the fractional derivative order from the 0.0 to the 2.0 order (order interval: 0.2). The ratio of performance to deviation (RPD), determinant coefficients of calibration ([Formula: see text]), root mean square errors of calibration (RMSEC), determinant coefficients of prediction ([Formula: see text]), and root mean square errors of prediction (RMSEP) were applied to assess the performance of predicting models. The results showed that models built on the fractional derivative order performed better than when using the classic integer derivative. Comparison of the predictive effects of 22 models for estimating clay content, calibrated by PLSR, showed that those models based on the fractional derivative 1.8 order of spectral reflectance ([Formula: see text] = 0.907, RMSEC = 0.425%, [Formula: see text] = 0.916, RMSEP = 0.364%, and RPD = 2.484 ? 2.000) and absorbance ([Formula: see text] = 0.888, RMSEC = 0.446%, [Formula: see text] = 0.918, RMSEP = 0.383% and RPD = 2.511 ? 2.000) were most effective. Furthermore, they performed well in quantitative estimations of the clay content of soils in the study area.

SUBMITTER: Wang J

PROVIDER: S-EPMC5608292 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Desert soil clay content estimation using reflectance spectroscopy preprocessed by fractional derivative.

Wang Jingzhe J Tiyip Tashpolat T Ding Jianli J Zhang Dong D Liu Wei W Wang Fei F Tashpolat Nigara N

PloS one 20170921 9

Effective pretreatment of spectral reflectance is vital to model accuracy in soil parameter estimation. However, the classic integer derivative has some disadvantages, including spectral information loss and the introduction of high-frequency noise. In this paper, the fractional order derivative algorithm was applied to the pretreatment and partial least squares regression (PLSR) was used to assess the clay content of desert soils. Overall, 103 soil samples were collected from the Ebinur Lake ba ...[more]

PMID: 28934274

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Project description:Accurate determination of clay minerals can be challenging due to the natural occurrence of interlayered phases, i.e., layers of different clay species such as illite and smectite. The overlap of peaks of the constituent minerals (e.g., illite and smectite), and the similarity of diffraction patterns when not treated with ethylene glycol, hampers identification, especially when the clay content is low. We investigated the occurrence of interlayered illite/smectite in a rock sample from Rodalquilar, Spain, using X-ray diffraction, scanning electron microscopy and reflectance spectroscopy in the short-wave infrared wavelength range. For the first time, a precise determination of interlayered I/S conducted on the extracted clay fraction treated with ethylene glycol using such different approaches was provided. X-ray diffraction results demonstrated the presence of an I/S peak at around 8.4° in the untreated fraction coupled with a peak splitting at 6.7° and 9.4° 2θ when solvated with ethylene glycol. While spectroscopy indicated the occurrence of interlayered structures as a mixture of the two constituent minerals, the results of X-ray analysis showed that the interlayered clay consisted of two discrete phases (illite and smectite). The two discrete phases were observed in both the whole rock analysis and in the extracted clay fraction. This study shows that X-ray diffraction and validation with a scanning electron microscope is a mandatory, integrating tool for detecting interlayered phases since reflectance spectroscopy alone cannot be used to differentiate between interlayered clay minerals and non-interlayered mixtures. This work highlights the limits and advantages of three sensors (X-ray diffraction, scanning electron microscopy and reflectance spectroscopy) to investigate clay mixtures and interlayering, representing a significant contribution to confidence in the interpretation of interlayered clays, this being essential in mineral exploration and prospecting.

Dataset Information

Desert soil clay content estimation using reflectance spectroscopy preprocessed by fractional derivative.

Publications

Desert soil clay content estimation using reflectance spectroscopy preprocessed by fractional derivative.

Similar Datasets

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