Discrimination between hydromorphic alluvial sandy mud paddy and tide sandy mud paddy based on hyperspectral characteristics.

The application of hyperspectral analysis techniques can extract hyperspectral characteristic parameters and identify soil types. In contrast to the traditional methods, this application is more convenient and time-saving. This paper took two types of Typic Hapli-Stagnic Anthrosols (the hydromorphic alluvial sandy mud paddy and the hydromorphic tide sandy mud paddy) in Xingguo County as the research objects to analyze the hyperspectal characteristics and to extract the effective hyperspectral absorption characteristic parameters (SAFP) for the two soils. In the research, we used three hyperspectral methods including the hyperspectral resample process, the continuum removal, and the first-order differential transform of hyperspectral reflectivity. The results showed that the wavelength position of peaks and valleys can be used to effectively identify the two different Anthrosols. The wave peak width, the wave valley width and the wave valley tilt angle were the parameters to distinguish the two types of Anthrosols. In addition, the analysis of the hyperspectral characteristics parameters after the hyperspectral resample process showed that the difference between the two types of soils was the wave peak reflectivity, and the wave peak reflectivity was the most effective parameter. The hydromorphic alluvial sandy mud paddy belonged to the high reflectivity mud type. The declining rate of the hydromorphic alluvial sandy mud paddy hyperspectral reflectivity was larger and the hyperspectral curve absorption width was significantly larger than that of the hydromorphic tide sandy mud paddy. Moreover, the analysis of the hyperspectral characteristics parameters after the continuum removal showed that the wave valley width can be used to distinguish the two types of Typic Hapli-Stagnic Anthrosols. The wave valley widths of the two soils were 26 and 178 nm, respectively in the vicinity of the wavelength 480 nm. Finally, the analysis of the hyperspectral characteristics parameters after the first-order differential transform of hyperspectral reflectivity showed that the wave valley tilt angle was the other effective parameter to distinguish the two types of Anthrosols. The wave valley tilt angle of the hydromorphic alluvial sandy mud paddy and the hydromorphic tide sandy mud paddy were -0.00573° and 0.00573°, respectively at the wavelength 471 nm. This showed that the hyperspectral reflectivity increase trend of the hydromorphic alluvial sandy mud paddy was negative in the vicinity of the wavelength 471 nm, while the hyperspectral reflectivity increase trend of the hydromorphic tide mud paddy was positive in the vicinity of the wavelength 471 nm. This paper can provide a reference for the application of hyperspectral analysis techniques to identify different Stagnic Anthrosols soil. [ABSTRACT FROM AUTHOR]