Abstract
This study provides the first integrated characterization of soils associated with natural populations of Capparis herbacea Willd. in southern Kazakhstan. Field surveys and soil sampling were conducted in June-July 2023 across three contrasting sites: (Population 1, Sogeti Gorge), piedmont plain (Population 2, Merki), and semi-arid lowland (Population 3, Saryagash) environments. Standard profile descriptions and laboratory analyses followed national GOST and classical pedological methods. Across sites, soils were alkaline (pH 7.8-8.9) and carbonate-rich, with low humus (0.18-6.3%). Texture ranged from light loam (P1) to medium loam (P2) and sandy loam (P3); moisture distribution varied from higher values in mountain soils (up to 21.6%) to more uneven patterns in semi-arid lowlands (6.5-20.7%). Available macronutrients were generally limited: P2 showed near-absent phosphorus, while P3 had relatively higher potassium. Salinity contrasted sharply: P1-P2 non-saline (total salts ~0.037-0.062%), whereas P3 exhibited moderate to strong salinity (0.082-0.910%), with upper horizons moderately saline and deeper horizons strongly saline, dominated by sulfates and calcium ions. These findings represent the first base-line data on soils supporting Capparis herbacea Willd. in southern Kazakhstan. Capparis herbacea Willd. demonstrates strong ecological plasticity, tolerating both carbonate non-saline and sulfate-enriched saline soils. Its adaptability highlights potential for use as a soil quality indicator and in restoration of degraded lands in Central Asia.