Abstract:In view of the problems of difficult digestion, large interference and volatile loss in the determination of total boron in soil, the alkaline melting method, microwave digestion method and micro-open graphite digestion method were used to detect and analyze the total boron in soil. The digestion conditions were optimized, and the three digestion methods were verified and compared. The results show that the types of alkali fusion agent and the amount of alkali fusion have a great impact on the accuracy of the alkali fusion method. When KOH is selected as the alkali fusion agent and the addition amount of KOH added is 3.0g, more accurate results can be obtained. The types of acid addition and the temperature of acid removal process have a major effect on the determination results of microwave digestion method. The optimal test results were obtained with acid addition system (5 mL HNO₃ + 1 mL HCI + 3 mL HF + 1.5 mL H₃PO₄) and removal temperature of 170.Different acid addition systems and digestion temperature also cause large errors in the determination results of micro-open graphite digestion method. When the acid addition system (5 mL HNO₃ + 1 mL HClO₄ + 3 mL HF + 1.5 mLH₃PO₄) is selected, and the digestion temperature is set as 170 °C. The determination results are more reliable. The verification and comparison results display that the limit of detection of alkali fusion method is 0.7 mg/kg, the limit of detection of microwave digestion method is 0.9 mg/kg, and the limit of detection of micro-open graphite digestion method is 1.0 mg/kg, which all meet the requirements of determination and analysis. Addition, the results of the three digestion methods exhibit satisfactory accuracy and precision, which can be used for the determination of total boron in soil, and there is no significant difference in the results of actual samples.The advantages and deficiency of the three digestion methods and the scope of application are different. In the actual test, the specific digestion method can be selected according to the number of samples and the approximate content of total boron in the sample. This work can provide reference for The 3rd National Soil Survey.