Method for detecting organic components of soil by utilizing near infrared spectrum

Abstract

The invention provides a method for detecting organic components of soil by utilizing a near infrared spectrum. The method comprises the following steps: (1) detecting organic matter chemical compositions of a plurality of calibrated soil samples; (2) acquiring diffuse reflection spectrograms of near infrared wavebands of the calibrated soil samples to obtain original spectrograms; (3) carrying out smooth pre-processing on the original spectrograms to obtain processed spectrograms; (4) establishing a quantitative relationship model between the processed spectrograms of the calibrated soil samples and the organic matter chemical compositions by adopting a vector machine method; and (5) acquiring diffuse reflection spectrograms of near infrared wavebands of soil samples to be detected, and detecting the organic matter chemical compositions of the soil samples to be detected according to the quantitative relationship model. The method provided by the invention can be used for rapidly and accurately detecting the organic matter chemical compositions of the soil to be detected by utilizing the near infrared spectrum.

Description

technical field [0001] The invention relates to the field of ecology, in particular to a method for detecting the chemical composition of soil organic matter. Background technique [0002] Soil organic matter (SOM) plays an important role in maintaining soil microorganisms, normal life activities of animals and plants, maintaining soil fertility and buffering properties, and regulating environmental climate. The key to studying SOM is to deeply understand its chemical composition and structure. The structure of SOM can be studied by chemical methods, pyrolysis mass spectrometry, solid-state carbon 13 nuclear magnetic resonance, etc. Among them, the cross-polarization and spin magic-angle 13 C solid-state nuclear magnetic resonance spectroscopy (Solid-state 13 CNuclear Magnetic Resonance with cross-polarization and magic angles spinning, CP-MAS 13 CNMR), because it does not need to extract organic matter by chemical or other methods, and can provide more comprehensive info...

AI Technical Summary

Problems solved by technology

Although there are many advantages mentioned above, the use of NMR to analyze the SOM structure also has some disadvantages: such as expensive instruments, time-consuming sample processing, long test cycle, special operation, high test cost, and difficulty in large-scale promotion, etc.

For example, with cross-polarization and spin magic-angle 13 C solid-state nuclear magnetic resonance spectroscopy (CP-MAS 13 CNMR) research on soil organic matter structure has the following disadvantages: 1. The instrument is expensive and the test cost is high; 2. The technical requirements are high and it is not easy to operate; 3. The test time is long (a sample often needs more than 24h); 4. The pretreatment is time-consuming ( Processing a sample requires several times of hydrofluoric acid treatment, water washing, and the final sample freeze-drying, which often takes several days); 5. It is not easy to promote

In addition, because it uses a linear method (such as the least square method) to establish a calibration model, the prediction accuracy is not high enough (the prediction correlation coefficients of many functional group carbons are lower than 0.80)

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