Relationship between mineral composition or soil texture and available silicon in alluvial paddy soils on the Shounai Plain, Japan

To evaluate the relationship between the amount of available Silicon (Si) in paddy soils and their mineral properties on the Shounai Plain in Japan, which is formed from several parent materials, we evaluated the amount of available Si, the particle size distribution, the oxide composition of crystalline minerals and the amount of oxalate-extractable Si (Sio), iron (Feo) and aluminum (Alo) in the soil. The amount of available Si in the soil and the oxide content of the crystalline minerals differed among four soil groups that were distinguished by their clay mineral composition. There was no difference in the particle size distribution among the soil groups. The amount of available Si was positively related to the SiO2/Al2O3 ratio of clay, the CaO concentration of silt and fine sand, and the amounts of Sio, Feo and Alo in the soil. The amount of available Si in the soils was negative correlated with the Na2O and K2O concentrations of silt, the K2O concentration of fine sand, and the coarse sand c...