Effect of Organic Matter Removal by Hydrogen Peroxide on the Determination of Soil Particle Size Distribution Using the Dynamometer Method

The dynamometer method of determining particle size distribution was developed several years ago. The principles of sample preparation for this method are based on those used in other sedimentation methods. With improvements in these procedures, an investigation of the effect on obtained particle size distribution results by removing organic matter using hydrogen peroxide was proposed. For this purpose, the particle size distributions were determined in 50 soil samples with varying organic matter content, before and after organic matter removal. A comparative analysis of the results, including calculation of the Euclidean distance, was performed on both groups. It was found that differences in the particle size distributions of the soils after the application of hydrogen peroxide were difficult to predict, and irregular in both magnitude and direction. However, in light soils, the process of organic matter removal caused an increase in the clay fraction at the expense of the silt fraction, which decreased. In soils with a higher initial clay fraction, there were decreases in the clay and sand fractions, while the silt fraction increased.