3.28. Where to get stored in Paris "standard fertility" of the soil? In 1900, Russian scientist Dokuchaev sent to the World Exhibition in Paris carved out of feather grass steppe near Voronezh cubic meters (1 x 1 x 1 meter) black soil. Voronezh black soil has become one of the main exhibits of the exhibition, received a gold medal and was recognized as "the king of the soil." He was subsequently identified as a standard fertility of the soil and placed in the International Chamber of Weights and Measures in Paris, where it is stored and the present time. The content of humus (organic macromolecular complex substances containing the basic elements of plant nutrition) in the soil reaches 14-16 percent.