Statistical indicators of variation of soil horizons depth and thickness at the experimental station “Oroshaemaya”

Abstract

The aim is to present statistical portrait of soil cover pattern for farm as series of cumulative statistical distributions of soil horizon’s depth and thickness. The object is soil combinations of Haplic or Luvic Protosodic Kastanozems and Solonetzs at the experimental station “Irrigated” localized in southern-western end of the Volga Upland near the Volga-Don Channel. Majority of empirical statistical distributions of soil horizon’s depth for general data fetch (182 profiles) cannot be approximated by normal one. Nonparametric indices are used. Separation of soil groups using substantial properties does not guarantee data fetches with normal distribution for all morphometric properties. Soil types and subtypes according to Russian soil classification system have different complex of statistical distributions of soil horizon’s depth. Many differences are related to changes of carbonate profile, development of secondary solonetzicity, crust formation, local surface washout and accumulation of upper part of arable horizon.