Nitrogênio e potássio em Steiner (2007)

Dr. Streicher: Another matter we are concerned with here is one that was brought very near to me in my youth. I grew up in the country, and was much concerned with the problem of manures for plant-life generally. The present position — the prevalent opinion on these matters — seems to me highly detrimental. The prevailing notions about manures have not gone far beyond what was inaugurated by Liebig, who wanted to instil mineral substances into the soil — nitrogen, phosphoric acid and potassium, for instance. The artificial manure industry in its present stage produces nitrogen bound to very strong acids — hydrochloric and sulphuric. Agriculture is faced with a new danger, which has even now become reality to some extent. Artificial manures are brought into the soil, regardless of the way the plants receive them. These artificials give rise to an acid reaction in the soil, and in a dry summer the results are disastrous. (Steiner 2007:77)

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