Abstract The 23 surface paddy soils (0–20cm) representing varying range of calcium carbonate (CaCO3) were collected to evaluate silicon (Si) supplying power and the factors which affect Si availability. A pot experiment and consecutive four‐year field trials were also carried out in this study to investigate the response of rice (Oryza sativa L. cv Wuyujing No. 3) and wheat (Triticum aestium L. cv Yangmai No. 5) to Si‐containing materials applied to the calcareous paddy soils. The result indicated that the available Si contents (sodium acetate‐extractable SiO2) of the soils surveyed were much higher than the accepted critical value. Stepwise regression analysis showed that pH value, clay, and CaCO3 contents significantly affected the available Si content. The pot experiment indicated that the grain yield, spike number, and filled grain percentage and ratio of grain/shoot of the Si‐treated rice markedly increased as compared to the control, but Si added had little effect on the shoot dry matter yield and 1...