Evaluation of desertification status in salt-affected soils of semi-arid rangelands using dis4me indicators

Desertification in semi-arid ecosystems is a multifaceted process influenced by factors such as climate variability and human-driven land and water management. Soil salinity further accelerates degradation by disrupting soil functions and reducing vegetation cover. This master's thesis evaluates the role of salinity in desertification risk using practical field and laboratory indicators within an indicator-based framework. The research was conducted in Balıbağı Village and its surroundings (Çankırı, Türkiye). In 2024, 30 topsoil samples (0–30 cm) representing rangelands were collected and analyzed for texture, bulk density, pH, electrical conductivity (EC), organic matter, total nitrogen, and CaCO₃. Desertification risk (ÇR) and environmental sensitivity (ÇDA) were calculated using the DIS4ME system. The findings indicate pronounced within-area variability in texture (sand 13–61%, mean 34.22%; silt 18–63%, mean 43.33%; clay 17–39%, mean 22.94%) and heterogeneous CaCO₃ content (5.22–20.72%, mean 11.29%), while pH remained stable within a narrow range (7.14–7.28; mean 7.19). Bulk density ranged from 1.04 to 1.47 g/cm³ (mean 1.26). Soil fertility indicators were generally low (organic matter 0.40–1.95%, mean 0.95%; total N 0.02–0.10%, mean 0.05%), whereas salinity levels were high (EC 6.27–10.33 dS/m, mean 7.77 dS/m; salt 2.22–4.20%, mean 3.20%). DIS4ME outputs show that ÇR ranged from 3.33 to 6.04 (mean 5.09; SD 0.77), clustering mostly in the moderate-risk class but reaching high risk at some points, while ÇDA ranged from 1.37 to 1.52 (mean 1.44; SD 0.05), remaining within a narrow band and concentrating in the Critical (C2) class. Overall, these results suggest a generally high sensitivity baseline across the area, with risk increasing locally depending on site conditions. Accordingly, the study recommends combining area-wide protective measures (maintaining ground cover, reducing erosion and soil disturbance, and improving organic matter and nutrient status) with targeted salinity-control actions in locations where risk is elevated (functional drainage where appropriate, careful water management, and regular monitoring of EC and salinity trends).