Plant and Soil

, Volume 126, Issue 1, pp 121-125

First online:

The effect of silicic acid on rice in a P-deficient soil

  • Jianfeng MAAffiliated withDepartment of Agricultural Chemistry, Kyoto University
  • , Eiichi TakahashiAffiliated withDepartment of Agricultural Chemistry, Kyoto University

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A pot experiment was conducted to analyze the effect of silicon on the growth of rice grown in a P-deficient soil and on P availability in the soil. Silicic acid was used, rather than a silicate salt, to avoid the complication of changes in soil pH.

Shoot dry weight on silicic acid treated soil (0.47 mg Si g−1 soil) increased significantly under both nonflooded and flooded conditions. Shoot Si concentration also increased although P concentration did not. Mn concentration decreased with silicic acid, resulting in a higher P/Mn ratio in shoots.

An adsorption and desorption experiment showed that silicic acid did not displace P nor decrease the ability of the soil to adsorb P. In contrast, Si desorption increased with increasing P concentration in the solution, and Si adsorption was reduced when P was applied first.

These results suggest that silicic acid does not increase P availability in soil. Increased dry weight may be attributed to a higher P/Mn ratio in the shoot, which may improve P utilization in the plant.

Key words

P adsorption P desorption P/Mn ratio rice silicic acid Yakuno soil