Evaluation of method of soil particle size distribution for the different soil texture

• 1、State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences
• 2、Institute of Soil and Water Conservation,CAS/State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau

Abstract：The particle-size composition is a basic soil physical property. Sieve-pipette method and Hydrometer method are the traditional approach to analyze the soil particle-size composition. The laser diffraction method is a new analysis instrument in recent years. However, due to the differences in the test principle, there are differences among the results of the three different method. This paper took two different texture of soil to study the discrepancy of the three methods mentioned above. It shows that：1）The precision shows that: the laser diffraction method is the best, the second is the pipette method and hydrometer method is the worst.2）The differences of the test results show that: when measuring particle 2-0.5mm, there now significant difference of the results among three methods for the two texture of soil; when it comes to <0.05mm particle size, for silty loam，the results from laser diffraction method are lower than the other two method, but no difference between this two methods；while for silty sand，the content result from Sieve- pipette is the highest, the hydrometer method is the second and the laser diffraction method id the lowest. 3) The laser diffraction measured results of different texture soil particle size distribution could be converted by the linear regression equation of following tow particles grades including 2-0.05mm and <0.05mm.

Keywords： Particle size distribution(PSD) Laser diffraction method Hydrometer method Sieve-pipette metod Method evaluation