Monitoring method of salt ion content in saline soil based on hyperspectral technology

Abstract

The invention discloses a monitoring method of salt ion content in saline soil based on a hyperspectral technology. The method comprises the following main steps: (1) collecting a soil sample in the wild and pre-treating the sample; (2) drying and sifting the soil sample; (3) measuring the total salt and eight salt ions in the soil sample; (4) carrying out hyperspectral measurement on the soil sample to obtain the original spectral reflectance characteristic curve of the soil sample; (5) processing the original spectral value, and carrying out correlation analysis between the spectral value and the measured salt ion content; (6) introducing the construction method of a support vector machine model, and performing model building and precision evaluation on the screened spectral transformation form. The monitoring method is relatively high in the prediction accuracy for each salt ion content in soil, provides a novel approach for the indoor measurement of the salt ion content in saline soil, and provides a novel way for achieving quick and lossless monitoring of the harm types of regional soil salinization.

Description

technical field [0001] The invention relates to the field of rapid monitoring of soil salinity, in particular to a hyperspectral technology-based monitoring method for salt ion content in salinized soil. Background technique [0002] Due to the joint effects of its soil parent material, topography, climate conditions and human factors, soil salinization and secondary salinization are seriously endangered in Xinjiang. This kind of land has low productivity, fragile ecology and harsh environment. The bottleneck of ecological construction. [0003] With the continuous development of remote sensing technology and image processing technology, the use of remote sensing has become the main means of soil salinization monitoring. Traditional soil salinization monitoring adopts field soil fixed-point survey method, which is not only time-consuming and laborious, but also has few measuring points and poor representativeness, which makes it impossible to realize large-scale real-time m...

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Problems solved by technology

[0007] (1) In the process of effectively extracting soil attribute information using hyperspectral technology, there is no good comparison of soil water content. Often, when measuring soil spectral information, the air-drying method is used based on experience or some existing research results. It is unclear whether the hyperspectral quantitative inversion of salt ions can be performed with fresh soil or dried

[0008] (2) As the soil particle size decreases, the reflectance of the soil surface increases, resulting in a decrease in the depth of the absorption peak, and the relationship between the spectral features of different bands and soil properties will change. Usually, soil spectra are measured using The 2mm sieve, whether other particle size treatments will improve the fitting accuracy in the determination of soil salt segregation remains to be further studied

[0009] (3) Indoor hyperspectral analysis technology can be widely used in the environmental assessment of soil resources because its influencing factors are easier to control than those in the field. The incident angle of indoor simulated light source has a significant impact on the hyperspectral measurement of soil properties, which may lead to different incident angles of light sources. There is no sharing of hyperspectral data among them. Therefore, the incident angle of the light source for the hyperspectral determination of soil salt ions is a problem that must be solved.

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