Abstract
Soil samples were collected from the saline soil of Al-Shiggah in Al-Qaseem, Saudi Arabia and were studied for their physico–chemical characteristics and algal flora. The soils were mostly sandy and moderately alkaline with electrical conductivities in excess of 4 mmhos cm−1 Sodium was the major soluble cation, chloride and sulphate were the principal soluble anions. The total soluble salts ranged between 4390–143000 p.p.m. Six species of blue-green algae and five green algae were identified. Two of the green algae (Dunaliella minuta and Protosiphon sp.) are reported for the first time from Saudi Arabiai. D. minuta, present in 17 samples, was the most frequently observed species. The salinity tolerance of D. minuta was determined.