The aim of the work is to study the process of transformation and formation of cultivated gray-brown soils under the influence of irrigation. The work was completed in 2014–2016 on the Kura-Araz lowland (Karabakh steppe) on irrigated gray-brown soils. Analyses of the selected samples were carried out by standard methods. Data on soil formation environment changes under the influence of irrigation in dry steppe zone conditions were generalized, modern processes of acculturation were identified and systematized. Stationary research has shown that the influence of ancient irrigation affects above all the formation of a new leaching regime in cultivated gray-brown soils and the gradual increase in soil profile due to irrigation deposits of different thickness (1–2 m). Every year an average of 1.0–1.5 mm of fresh irrigation deposits (8–12 t per ha) are accumulated on irrigated lowland. Irrigation is a powerful factor significantly changing soil; irrigated soils are separated into individual irrigation types. When watering with a considerable amount of suspended substances a new horizon with a high content of humus (2.39 %), nitrates (2.83 mg per kg), a developed microbial association (up to 4752 thousand units per ha), granular structure, high porosity (56 %) compared with virgin soils is formed on the surface of soils. According to their confinement to various relief elements and a number of morphological and physical-chemical properties, soils differ by state of cultivation: poorly cultivated, medium-cultivated, highly cultivated. The division of soils according to the cultivation state is carried out as a generic division. Types of cultivated soils differ by the power of agri-irrigation accumulations.
Key words: irrigation, soil-forming process, cultivated soils, agro-irrigation deposits, old-irrigated soils.
