Corn seedling response to silicon amendments in three Iowa and one Chinese soil

Silicon is an essential element in biological systems. It is required by mammals, plants, and microorganisms. It is well studied as a component of soil mineralogy, especially in the phyllosilicate (tetrahedron) structure. However, there remains a significant need to study more about how Si affects plant growth. This study seeks to address this need in a small way. Specifically this project evaluates the likely amount of Si in three Iowa soils and one Chinese soil, and whether Si influences early corn growth (seedlings) in a pot study. The soil series of interest in Iowa are Fayette, Harps and Ida. Seedlings were grown for 10 days. Silicon amendments were ground feldspar, ground quartz and powdered sodium silicate. Each amendment was mostly silt-sized when added to pots. Data collected included plant heights, above ground (stem and leaves) dry weights, below ground (aka, root) dry weights and selected chemical analysis of ashed samples. Results were variable although in general corn seedling heights varied proportionally to Silicon amendments. More specifically, corn stem and leaf weights were highest with high feldspar application although, interestingly, they were lowest with low feldspar application. Comparing across soils, the weights of corn stems and leafs were higher in Harps than Fayette. Roots did not show much response with Si treatments. From a SEM analysis of ashed plant tissue samples it was determined that Si is not evenly concentrated in the plant and that the root Si concentration always higher than the Si concentration in stems and leaves.