• Spectroscopy and Spectral Analysis
  • Vol. 38, Issue 10, 3238 (2018)
LIU Huan-jun1、2、*, WANG Xiang1, LI Hou-xuan1, MENG Xiang-tian1, JIANG Bai-wen1, ZHANG Xin-le1, and YU Zi-yang1
Author Affiliations
  • 1[in Chinese]
  • 2[in Chinese]
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    DOI: 10.3964/j.issn.1000-0593(2018)10-3238-07 Cite this Article
    LIU Huan-jun, WANG Xiang, LI Hou-xuan, MENG Xiang-tian, JIANG Bai-wen, ZHANG Xin-le, YU Zi-yang. Effect Mechanism of Soil Minerlas on Spectral Characterisitics of Main Soil Classes in Songnen Plain[J]. Spectroscopy and Spectral Analysis, 2018, 38(10): 3238 Copy Citation Text show less

    Abstract

    Although the analysis of the reflectance spectral characteristics of pure minerals and the establishment of a database have been carried out, the test of primary minerals and clay minerals in soils is mainly qualitative, which means that it is possible to determine what minerals are contained in soils. However, it is difficult to accurately determine the contents of minerals. Soil minerals are the intersection of pedology and geology, which is easy to be ignored, especially the effects of soil minerals on soil reflectance spectral curves has been neglected in other researches. In this paper, we discussed the effects of soil minerals on the characteristics of soil reflectance spectra in the visible and near infrared region (400~2 500 nm), and clarified the main mechanism about affecting the characteristics of soil reflectance spectra. Soil samples were collected in the Heilongjiang part of Songnen Plain in 2014, including four great groups and seven genera, a total of 54 soil samples. After grinding and sifting, the soil samples were measured in the darkroom to obtain reflectance spectrum data. The reflectance spectrum data of soil minerals were obtained from the 2017 USGS mineral spectral library. We smoothed spectral reflectance data with nine points, resampled at 10-nm intervals and continuum removal. The mineralogical phases of the samples were detected by an X’Pert-Pro XRD (Philip, Holland). The contents of primary minerals, such as quartz, feldspar, calcite and amphibole, and clay minerals such as montmorillonite, illite and kaolinite were measured. First of all, we analyze the reflectance spectral characteristics of seven genera, and determine the shape characteristics and absorption position of spectral curves of each genus. Secondly, we analyze the mineral content of genera, and find out the commonness and difference of each mineral content of different genera. Thirdly, we analyze reflectance spectral characteristics of different primary minerals and clay minerals, and determine the shape characteristics and absorption position of different soil minerals. Finally, we combine the spectral characteristics of different genera, mineral content of different genera and spectral characteristics of soil minerals, the following conclusions are obtained: (1) The skeleton characteristics of soil reflectance spectra are determined by soil minerals, and the effect of soil minerals on reflectance spectra of genera is the most obvious, however, the effect at great group level isn’t obvious due to the existence of various reflectance spectral characteristics of great group. (2) The effect of clay minerals on soil reflectance spectral characteristics is greater than primary minerals, mainly by clay minerals such as montmorillonite and illite, but feldspar and kaolinite affect sandy soils. (3) Montmorillonite determines the characteristics of the first absorption valley, the illite determines the second valley, kaolinite determines the two small absorption valleys before 1 400 and 1 900 nm, and microcline and albite determine the first and second valleys of sandy soils. (4) When the content of montmorillonite is high enough, the spectral characteristics of kaolinite and feldspar will be completely masked, and the spectral characteristics of illite will be partially masked. With the decrease of montmorillonite content, the spectral characteristics of illite will be gradually reflected. When the content of montmorillonite and illite decreases to a very low level, the spectral characteristics of kaolinite and feldspar minerals gradually manifest. The results explain the reasons for the differences in spectral characteristics of different genera, which can provide theoretical basis for soil spectral classification, detailed soil mapping and mineral distribution based on hyperspectral images.
    LIU Huan-jun, WANG Xiang, LI Hou-xuan, MENG Xiang-tian, JIANG Bai-wen, ZHANG Xin-le, YU Zi-yang. Effect Mechanism of Soil Minerlas on Spectral Characterisitics of Main Soil Classes in Songnen Plain[J]. Spectroscopy and Spectral Analysis, 2018, 38(10): 3238
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