Comparison grain size analytical results in loess, soil between laser and hydrometer method

It is important to examine the performance of the laser method and hydrometer methods and to understand its discrepancy. In the present study, the grain size of loess and soil samples are measured by laser particle size analyzer and hydrometer methods, respectively. To compare analytical results using different methods, it is shown that the reproducibility and measurement precision of the laser particle size analyzer are better than those of hydrometer methods. It suggests that the content of clay particles (5 μm) is somewhat lower and mean size is coarser in laser particle size analyzer than in hydrometer methods. Differences in the measure results between the laser method and hydrometer methods may be attributed to the various principles of the methods and the particle shape. It indicates that grain size of secondary carbonate in loess and soil, which was mainly formed during soilforming process, may be less than 5 μm.