Reclaiming saline areas in Khorat Basin (Northeast Thailand): Soil properties,species distribution,and germination of potential tolerant species

The objective of this study was to investigate the potential of native Thai species for reclaiming salt-affected areas in Thailand. Plant species diversity in Nakhon Ratchasima Province in northeast Thailand, and their soil characteristics (texture, electrical conductivity (EC_e), exchangeable sodium percentage (ESP), and pH) were measured. A total of 19 species in 16 genera of 12 families were found, among which the most abundant species belonged to the Poaceae and Cyperaceae families. The highest values of EC_e were found near the surface (0–20?cm) with an average range between 30–80?dS?m^?1, while lower values in the range of 15–25?dS?m^?1 were found at lower depths (20–100?cm). Soil conditions in the subplots with plant coverage showed lower EC_e and ESP when compared to plots without vegetation. Seeds from the three most frequently occurring species, including Azima sarmentosa, Gymnosporia mekongensis, and Buchanania siamensis, were then tested for germination at different salinities. Seeds of all three species germinated at high salinities, from 25–45?dS?m^?1, with total germination ranging 40–90%. Together with the ability to germinate at high salinities, these native species showed deep, rapid root elongation, likely to escape high surface EC_e levels (approximately the top 30?cm). Planting these species in areas with vegetation coverage would aid successful reclamation of saline areas. Reclaiming salt-affected soils will not only improve local farmer’s economic status, but can also reduce the extent of deforestation, benefiting the entire ecosystem.