Importance of Silicon in Soils and Plants

The crust of the earth is largely composed of silicon that is found primarily as silicate minerals,
secondary alumino silicates and various forms of silicon dioxide. However, the abundance of silicon in
soils is not an indication that sufficient supplies of soluble silicon are available for plant uptake. In this
chapter, the outcomes of many years of research conducted on silicon are consolidated to understand
the state of knowledge for silicon fertilization guidelines in crop production. The monosilicic acid
(H4SiO4) is the form of silicon used by plants, which is found both in liquid and adsorbed phases of
silicon in soils. Silicon plays a very important role in drought tolerance because silicon fed plants
maintains higher leaf water potential. This is assumed to be due to the formation of silica cutical
double layer on the epidermis.