Work

Decoding seasonal variation in soil physical, physico-chemical and hydraulic attributes driven by altitudinal gradients in the alpine wetlands of Lesotho

Year: 2026

Type: article

Abstract: Altitudinal gradients significantly influenced soil physical, hydraulic, and physico-chemical properties across seasons in Lesotho’s alpine wetlands, yet these ecosystems remain largely understudied. This study evaluated composite seasonal index and examined soil variation, and seasonal changes in soil attributes across altitudes (2500–3155 m a.s.l.), equivalent to wetlands from three sub-catchments (blocks): Khorong and Tenesolo (Senqunyane), Khamoqana and Khalong-La-Lichelete (Sani), and Lets’eng-La-Likhama and Koting-Sa-ha Ramosetsana (Khubelu), during the standard (spring, September 2024) and peak (summer, February 2025) wet seasons. The soil samples were collected in September 2024 (standard) and February 2025 (peak) wet seasons and analyzed for bulk density (BD), saturated hydraulic conductivity (Ksat), infiltration rate (IR), water holding capacity (WHC), texture, pH, electrical conductivity (EC), cation exchange capacity (CEC) and soil organic carbon (SOC) following standard procedures. Soil texture showed a clear altitudinal gradient, with sand decreasing from 64.97% at lower elevations to 39.79% at higher elevations, while silt and clay increased, shifting soil texture from sandy loam to loam. Seasonal changes were relatively small, with the greatest variation observed in Ksat (13%) and BD (6.8%). SOC increased slightly (∼ 0.4%) in summer, with the highest values at Koting-Sa-ha Ramosetsana. Correlations showed strong relationships among texture, BD, IR, WHC, Ksat, and SOC, indicating their interconnected influence on soil hydraulic and carbon properties. Overall, these results underscore that seasonal hydrological dynamics and elevation jointly shape soil structure, water movement, and carbon storage in Lesotho’s alpine-wetlands, emphasizing their ecological sensitivity and need for targeted conservation.

Source: Physics and Chemistry of the Earth Parts A/B/C

DOI: 10.1016/j.pce.2026.104860

Authors: Mosiuoa Mochala, Knight Nthebere, ‘Mamohau Thamae, Krasposy Kujinga, Makoala Marake, Jean-Marie Kileshye Onema

Institutions: National University of Lesotho, North-West University

Language: English

Topic: Soil and Unsaturated Flow

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Life on land, Climate action

Open Access status: hybrid

Estimated APC paid: $2,900