Ehrenfried Pfeiffer is one of the pioneers of the biological-dynamic method of agriculture, who worked for many decades as a practical farmer, enterprise manager, consultant and researcher. The biological-dynamic method allows you to obtain biologically complete food products, improve soil quality, and makes the agricultural enterprise healthier and economically sustainable."Earth Fertility" includes a discussion of the spiritual-scientific foundations of the biological-dynamic approach, a description of methods for processing manure, preparing compost, choosing an improving sequence of crops and other practical recommendations, as well as figures and facts characterizing changes in the condition of the soil, livestock productivity and etc. when restructuring the farm using the biological-dynamic method. About all this and more in the book Earth Fertility, its maintenance and renewal (Ehrenfried Pfeiffer)