More than 40 states have approved the use of CrossOver, a highly refined blend of calcium and magnesium silicate in pelletized form, as a soil amendment.

California has approved the product from Harsco Metals and Minerals, Sarver, Pa., for use only on monocots, such as corn and rice, according to a news release.

Although researchers don't fully understand silicon's role in fighting biotic—or biological—stressors, such as diseases, they have a better understanding of how it helps with abiotic stresses, such as drought.

Not all forms of silicon can be taken up by the plant, either. Only soluble forms can.

The form of silicon taken up by plants is silicic acid, according to information from Cornell University Cooperative Extension.

For agricultural use, it's typically supplied as potassium or sodium silicate.

After uptake by the plant, silicic acid forms a silica gel between the cuticle and cell wall and between the cell membrane and cell wall.

These layers act as physical barriers to reduce evaporation.

Among the stressors CrossOver improves are salt stress, drought and heat stress, plant structural integrity, root activity and growth, and photosynghetic activity, according to the release.