Silício, potássio e cálcio em Steiner (2007)

Silicic acid contains silicon as you know, and silicon, too, is transmuted in the living organism — transmuted into a substance of great importance, which, however, is not yet included among the chemical elements at all. Silicon is transmuted. In time, we need the silicic acid to attract and draw in the cosmic properties. Now in the plant there simply must arise a clear and visible interaction between the silicic acid and the potassiumnot the calcium. By the whole way in which we manure the soil, we must quicken it, so that the soil itself will aid in this relationship. (Steiner 2007:47)

STEINER, Rudolf. 2007. The Agriculture Course. (Trans.: George Adams) Shrewsbury: Wilding & Son Ltd.