The place of the alluvial-meadow-forest soils of the southern slope of the Great Caucasus within Azerbaijan in the international system WRB

The aim of the study. The aim of the research was obtaining new information about the genesis, current status, diagnostic features and properties of the alluvial-meadow-forest soils of the southern slope of the Great Caucasus within Azerbaijan and to perform the taxonomic attribution of those soils in accordance with the International Classification of Soils in compliance with the Reference Base for soil resources (IUSS Working Group WRB, 2014). Location and time of the study. Alluvial-meadow-forest soils of the southern slope of the Great Caucasus within Azerbaijan were the objects of the study. Methodology. Field experiments (relief, vegetation, laying of soil profiles, their description, selection of soil samples and establishment of a preliminary classification name of the soils) and physico-chemical analyzes of soil samples (humus and total nitrogen content, ratio of C:N in soil organic matter, soil pH, cation exchange capacity, grain-size analysis, water extract composition) were carried out by standard methods. Results. It was established that the most characteristic features of alluvial-meadow-forest soils are as following: blocky angular, blocky subangular and granular structure of the upper horizon, medium loamy, heavy-loamy granulometric composition of the profile, mostly gray, dark gray or dark brown color overcomes. According to the humus content, they are highly humic, in the upper accumulative horizon (A1h) contains 5.91% of humus (soil profile No. 308). The drop in humus content is quite sharp, which is typical of soils of forest origin. In the alluvial-meadow-forest gleyic soil, the humus content in the upper horizons is 3.45-2.82%, and sharply decreases with depth - 1.14% and in the buried humus horizons it increases again to 1.25-1.36% (soil profile no. 505). The absorption capacity in alluvial-meadow-forest soils (soil profiles no. 308, no. 462 and no. 470) in the upper horizons is high: 38.60, 31.80 and 38.60 cmol (eq) / kg of soil, and in alluvial meadow-forest gleyic soils (soil profile No. 505) average - 20.31 cmol (eq) / kg of soil. Ca dominates in the exchange bases. The reaction of the soil environment is slightly acidic, neutral and varies in the range of 5.5-7.8. The soils are not saline. Conclusion. For the first time, an attempt is made to determine the name of alluvial-meadow-forest (alluvial-meadow-forest cultivated, alluvial-meadow-forest gleyic pebble, alluvial-meadow-forest pebble, alluvial-meadow-forest gleyic soils) in accordance with the International Classification of Soils in compliance with the Reference Base for soil resources (WRB) 2015. The above soils are assigned to the Fluvisols reference soil group with various principal and supplementary qualifiers.