The soil particles of the "whitish harizon" in bleached paddys were separated into seven fractions (1-0.25,0.25-0.05,0.05-0.01,0.01-005,0.005-0.002,0.002-0.001 and<0.001mm).Chemical analysis showed that the sand fraction (1-0.05mm) in which there are "iron-manganese sands" contained less SiO₂ and Fe2O3 than the silt fraction (0.05-0.002mm).The sand fraction was characterized by its very high magnetic susceptibility.Its hygrosqopic coefficient was also higher than silt fraction by 3.5-4.0%.These features of the soil are different from those of the upland sails.This implies that in addition to SiO₂,other minerals may also be present in the sand fraction.Experimental results confirmed that it was pnly the clay fraction(<0.002 mm) which could exhibit plasticity and swelling properties.The plastic index and swelling capacity of the fine clay(<0.001 mm) were higher than those of the coarse clay (0.002-0.001 mm) by 2-3 times.The compressive strength of the silt fraction was very low (0.014-0.147 Kg/cm²),but its bulls density in water was greater (1.37-1.42g/cm²).Under waterlogged csondition the silt fraction settled down as a compacted layer.The settling and compacting of the "whitish horizon" might be mainly affected by the content of coarse silt (0.05-0.01mm) and the ratio between coarse silt and fine clay.It is considered that the eribical limits for a soil to exhibit settling and compacting properties are: coarse silt content ≥40%,ratio between coarse silt and fine clay content ≥2,and the organic matter content ≤2%.