Determination of soil organic matter by automatically potentiometric titration method

Soil organic matter(SOM) was determined by Tyurin method with manual titration and automatically potentiometric titration.The precision and recovery rate of automatically potentiometric titration was studied.The concentration of FeSO4 standard solution of was calibrated by both automatically potentiometric titration and manual titration method.The results indicated that there was identical and no remarkable difference for calibration of FeSO4 standard solution by two methods.There was no significance difference for determining SOM by Tyurin method with manual titration and automatically potentiometric titration method which showed two methods could meet analysis requirement.Automatically potentiometric titration method revealed a good accuracy and reproducibility with recovery rate of 98.43%～101.8% and RSD of 0.693%～0.936%.It was obvious automatically potentiometric titration method could be recommended as a good method to determine SOM.