Soil morphological, chemical and salinity characteristics of Capparis herbacea Willd. populations in Southern Kazakhstan

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.