The soils of natural populations of Gentiana tianschanica Rupr. (Gentianaceae) in Ile Alatau, Kazakhstan

Abstract

The article presents findings from field and laboratory studies conducted on the soils within the habitat of the Gentiana tianschanica Rupr. population. Various parameters including soil types, morphological characteristics, nutrient elements, humus content (Soil organic matter), absorbed bases, soil pH, granulometric composition, and salt content were analyzed through soil chemical analysis . A detailed analysis of the physical and chemical properties of soils sampled from three pedons (P-1, P-2, P-3) within the Kimasar gorge region. The soils were sampled at various depths ranging from surface layers (0–10 cm) to deeper layers (70–80 cm or 90 cm). Laboratory analysis of mountain meadow chestnut soils revealed moderate (soil organic matter) humus content (2.84% to 6.18%) and neutral to slightly alkaline pH values (6.0 to 6.66), indicating a balanced soil environment. Total calcium carbonate (CaCO3) content varied across pedons, with moderate levels in P-1 (27–44 g kg^-1) and higher values in P-2 (44 mg-eq/100 g in soil), suggesting a moderate lime content. Organic matter content was notably higher in P-2, especially at the surface (18.8%), compared to P-1 (6.18%) and P-3 (10%). Cation exchange capacity (C.E.C.) was also higher in P-2 (50.2 mg-eq/100 g in soil), indicating a greater nutrient-holding capacity, while nitrogen content was highest in P-1 (42 mg/kg at the surface). Phosphorus levels were particularly elevated in P-2, especially in the surface layer (140 mg/kg), whereas potassium levels were moderate across all pedons. The granulometric composition showed significant variation, with P-1 exhibiting a mix of sandy clay and clay loam, P-2 showing clay loam and sandy clay loam, and P-3 consisting of silt loam and loamy sand. a characteristic shared with the dark chestnut soils of the Big Almaty and Kaskelen gorges. As a result of the study, all soil types studied were found to have a non-saline composition based on total salt content analysis. These variations in soil texture and nutrient content reflect the complex interactions between local geological and hydrological factors, influencing soil formation, structure, and fertility, which in turn affect plant growth and ecosystem dynamics in the region.