A field study was conducted for two years in three semi-arid regions of Syria in order to define, under field conditions, the wheat (Triticum aestivum L.) yield response function to irrigation water salinity and to study the process of soil salt accumulation. The three regions experience similar climatic conditions (semi-arid Mediterranean climate) but have different soil textures, varying from sandy loam to clay. The study involved 74 farms all of which had been irrigating for more than 3 years prior to this study, with well water of different salinity values (0.44 to 14.1 dS/m). All of these farms operated with similar cultural practices. / Results indicate that the wheat yield response function to irrigation water salinity differs between the three regions. The irrigation water threshold salinity value beyond which wheat yield started to decline, was found to be 6.5 dS/m, 3.5 dS/m and 1.2 dS/m in the Khabur low plains; Aleppo south plains and Shedadeh area respectively. Wheat was more salt tolerant to irrigation water salinity in sandy loam soils than clay loam soils. The three threshold values obtained in this study are different from the "universal" value of 4 dS/m which is proposed in current literature. The "universal" value was obtained from artificially salinized field plots seeded under non-saline conditions. / In addition, it was found that salt accumulation in the soil profile increases as soil clay content increases. / The results demonstrate the necessity of establishing regional water quality criteria when planning the use of saline water sources for irrigation in semi-arid regions.

No description available.