Humus Theory

Principles of Agriculture, 1809-12

Thaer’s most quoted book is the four volumes Grundsätze der rationellen Landwirthschaft (1809–1812), which was translated into English in 1844 as The Principles of Agriculture by William Shaw and Cuthbert W. Johnson. The humus theory described in this work still received acceptance in the Modern Period (1800–1860).

Von Thaer’s “Principles of Agriculture” contain the result of his experience through a series of years. The work embraces the theory of the soil, the clearing of land, plowing, manuring, and irrigation, hedges and fences, management of meadow and pasture lands; the cultivation of wheat, rye, corn, oats, barley, buckwheat, hops, tobacco, clover, and all the varieties of grasses; the economy of kine stock, breeding and feeding; the management of the dairy, and the use of manures, and the various systems of cultivation, keeping journals and farm records. In brief, it is a complete cyclopedia or circle of practical agriculture.

By the time the book was translated, in 1833, it had been frequently expressed by persons conversant with Foreign agricultural publications, that Von Thaer’s Work should not have been translated into English. It was admitted by some of the first agricultural writers, who have read the work in the original language, to contain a great mass of valuable practical matter.