Abstract
Central Asia is well-known for its productive irrigated lands and pastures. However, the region is currently dealing with serious land degradation and soil salinization issues. This article discusses the problem of soil salinization in the Kazakh part of the Myrzashol massif (The Hungry Steppe), where irrigated agriculture is developed. The reclamation state of the soil cover in this massif was assessed using field and laboratory studies from 1995 to 2014 and from 2014 to 2020. In the study area, in the period from 2015 to 2020, several samples were continuously taken before the growing season, as well as after the growing season at 529 wells for sampling the level and mineral composition of groundwater and the chemical composition of the soil. If in 1995, out of 125.4 thousand hectares of irrigated land, 31.8 thousand hectares (25.4%) were moderately and heavily salted, then in 2020, out of 146.5 thousand hectares of land, 57 thousand hectares (38.7%) were subjected to secondary salinization. Over the last 25 years, the area of moderately and heavily saline lands on the irrigated Myrzashol massif has grown by 25.2 thousand hectares. Before the transformation of the Myrzashol zone into an irrigated one, the groundwater level was within 15-30 m. In 2020, the groundwater level on the irrigated area of 3622 ha was 0-1 m (in 1994 it was 105 ha), on 38,155 ha (in 1994 it was 7,792 ha) - 1-2 m. The results of the study showed that the increase in the level of salinity of the soil cover is associated with an increase in the groundwater level due to the poor level of irrigation systems, as well as the weak filtration capacity of soils.