Si is a second widespread element on the Earth. Except inert forms of silicon (Quartz,
glass et al.) in the nature presents biogeochemical active Si. This forms has effects on different
soil processes and growth of microorganisms and plants. The biogeochemical cycle of Si in the
nature more intensive then P or K cycle in the terrestrial ecosystems.
Use of soil under agricultural cultures destroys a balance of nutrients as far as their
significant part is harvested with crop annually. Silicon, as well as other nutrients, is carried out
of the soil. The removal of active Si from cropland ranged from 40 to 300 kg Si per ha.
Increasing Si deficit causes a number of negative consequences because silicon is not only
a nutrient for plants and microorganisms but also a constructive soil element. The lack of active
Si leads to degradation of soil fertility. Si plays important role in plant. This element controls
root system development, increases plant resistance to abiotic (low or high temperature, wind,
salt, heavy metals, hydrocarbons, Al et al.) and to biotic stresses (insect, fungi, diseases).