The place of the Zheltozem-Gley Soils of 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 Zheltozem-Gley Soils of the Lankaran region of 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. Zheltozem-Gley Soils of the Lankaran region of 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 the irrigated zheltozem-gley soils were as following: blocky angular-subangular structure of the upper horizon, clayiness of the entire soil profile, the presence of iron-manganese concretions and ferruginous mottles. A gradual decrease in the content of humus (from 2.15-3.28 to 0.18-1.24%), nitrogen (from 0.17-0.24 to 0.05-0.24%), the ratio of C:N (from 6.64-7.18 to 1.89- 5.91) was found. The cation exchange capacity increased down the profile (from 33.37-37.13 to 34.31-40.89 cmol (eq)/kg). The reaction of the soil environment was weakly acidic, and varied within 5.8-6.0. Under the influence of irrigation, the removal of the silt fraction from the upper horizons and its accumulation in the middle horizons of the soil were observed (42-96 cm - 42.4%, 48-87 cm - 28.8%). According to the granulometric composition, these soils were medium-light-heavy loamy. The soils were not saline.Conclusion. For the first time, an attempt was made to carry out the taxonomic attribution of Zheltozem- Gley soils (irrigated Zheltozem-Gley merged, ordinary Zheltozem-Gleyic, irrigated Zheltozem-Gley, irrigated residual calcareous Zheltozem-Gley) according to the international classification of soils based on the Reference Base for soil resources (WRB). With the different principal and supplementary qualifiers, all soils were classified as Lixisols.