Microbial Transformation of Silicon in Soil

Silica (from Latin “silex” means to flint) is rarely found on its own and often combines with oxygen or other elements to form silicates which are regarded as the largest class of rock-forming materials. In nature, they occur as distinct polymorphs as silica or oxides of silica in either crystalline or amorphous form and their mineral weathering releases mono silicic acid which is assimilated by plants, adsorbed on minerals, transported to watersheds, or trapped in clay minerals. Being placed in group IV of the periodic table, carbon (C) and Si shares several characteristics and significance including that of C biotransformation and cycling. However, although Si compounds are abundant in soil, their availability to plants is limited. These compounds help to render resistance to plants against biotic and abiotic stress. Si is known to have a wide range of plant beneficial properties, yet regarded as a nonentity in plant nutritional aspect. This chapter details a suite of factors associated with silica in soil and plant systems.