Combinatorics and Soil Classification

Abstract

Experimental data on 1029 soil profiles examined in the area of the Chashnikovo Experimental and Training Soil-Ecological Center of Moscow State University in Moscow region were used to create an enumerative classification at the level of the groups of soil horizons according to the theoretical concept of a machine generator of soil classifications suggested by V.A. Rozhkov and the concept of logical possibilities suggested by G.A. Zavarzin. Combinatorics of the sets of features of 17 diagnostic horizons separated into eight groups made it possible to characterize 255 possible combinations of the groups of horizons. In turn, the space of logical possibilities consisted of 168 combinations. In the real space, the number of combinations decreased to 46, i.e., by 3.6 and 5.5 times compared to the logical and universal spaces, respectively. The relationship between the separated groups of combinations of soil horizons and the subtypes of soils identified in the Classification and Diagnostics of Soils of the Soviet Union (1977) was as follows: any given combination does not belong to two different subtypes, but a given subtype may include several combinations. This made it possible to link the suggested enumerative classification and the classification system of 1977 to ensure mutual transition between these classification fields.