Key Laboratory of Synthetic and Natural Functional Molecular Chemistry of Ministry of Education;
College of Chemistry&Materials Science;
Northwest University;
Xi'an 710069;
People's Republic of China;
College of Chemistry and Chemical Engineering;
Xi'an Shiyou University;
Xi'an 710065;
People's Republic of China;
laser-induced breakdown spectroscopy(LIBS); random forest; soil pH; quantitative analysis;