Dariush Ahadi Ravoshti - Department of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran
Ahmad Baybordi - Department of Agriculture, University of Tabriz, Tabriz, Iran
Leila Farjam Haji Agha - Department of Agriculture, University of Maragheh, Maragheh, Iran

This study is present the comprehensive work on groundwater quality estimation for Bonab Plain located in East-Azerbaijan, northwest of Iran. In this regard, experimental procedure concluded electrical conductivity (EC), sodium adsorption ratio (SAR) and united states salinity laboratory diagram (USSL) to provide the empirical classification of groundwater quality in the Bonab region. In experimental stage, the ۲۵ sample of the Bonab Plain groundwater was taken and conducted the laboratory tests to preparing USSL requirements then in classification stage, used the USSL diagram to preparing the irrigation waters classes as well as qualities. As results it has been determined that the water samples of Bonab plain is in located on C۲S۱ and C۳S۱ classes based on USSL classification which is indicated the low to moderate salinity.

USSL classification, Groundwater quality, Sodium adsorption ration, Electrical Conductivity, Bonab