Laser-induced Breakdown Spectroscopy Analysis of Soil Nutrient Elements Based on Two-dimensional Correlation Method

There are many spectral peaks of soil nutrient elements in laser-induced breakdown spectra.In order to explore nitrogen，phosphorus，and potassium nutrient element peaks for model analysis，laser-induced breakdown spectra of soil samples in the range of 188-981 nm were collected，and analyzed by two-dimensional correlation method.Sensitivity of characteristic wavelengths were analyzed by auto-peaks of synchronous spectra，relationship between characteristic wavelengths were analyzed by cross-peaks of synchronous and asynchronous spectra，and excitation difficulty was compared by energy level.Results showed that：498.174，499.101，499.948 and 500.717 nm spectral lines were suitable for nitrogen element analysis；253.323 and 253.649 nm spectral lines were suitable for phosphorus element analysis；766.414 and 769.970 nm spectral lines were suitable for potassium element analysis.The preferred spectral lines could provide theoretical support for soil nutrients detection by laser-induced breakdown spectroscopy.