The research presents mineralogical studies of irrigated and non-irrigated sierozem soils of the Shaulder irrigation massif of Turkestan Region, Kazakhstan. Soils and soil cover representations comprised zonal soils, southern sierozem, and intrazonal soils: meadow and meadow sierozem soils forming combinations with meadow and common solonchaks. The southern light sierozem soils occupy the highest surfaces of the ancient alluvial plain-hilly foothills. The analysis of the fine-dispersed part of southern sierozems showed a mineralogical composition. In the upper horizons of irrigated sierozem soils of southern and meadow sierozem soils, the silt accumulation occurs, ranging from 14.5% to 18.9% and from 8.3% to 11.8%, respectively. The upper part of the irrigated sierozems profile (0–40 cm) has dominant hydrous minerals (27%–32%); however, their quantity decreased at the considerable depth. The maximum amounts of silicon oxide, phosphorus, and aluminum oxide were prevalent in the studied soils’ arable layer. Compared with the soil, the bulk chemical composition of the silty fraction showed a decrease in the amount of SiO; however, a significant increase appeared in the gross Mg, Fe, and Al. In the arable layers, the enhanced content of hydromica revealed the hydrosludge process of the silty fraction. It occurs as a result of physical dispersion of mica material of large fractions and destruction of the small amount of smectite phase, reorganizing the fine-dispersed part of the soils due to irrigation.
Mineralogy, irrigated and nonirrigated soils, sierozem, hydromica, layer formations, kaolinite, chlorite, quartz
For the first time, the studies of silty fraction of southern and meadow-sierozem soils of Shaulder massif of Turkestan Region, Kazakhstan succeeded. The meadow-sierozem soils contain illite, glauconite (hydromica) kaolinite, halloysite, chlorite (clinochlorine), quartz, and feldspars. The magnesian aluminosilicates also accompanied the chlorite-kaolinite-hydrosludite association. Moreover, an observation took note of mineral trona occurring in non-irrigated meadow-sierozem soils. Irrigation for the known effects not only affects the humus state, physical, and chemical properties of soils, but also alters the conservative mineral component of the fine-dispersed fraction.