Evaluating quality of ground water resources for irrigation, Roudab Plain, Sabzevar

Evaluation of Ground water quality to make use in agricultural industry is of special interest. The purpose of this study is to assess ground water quality used in irrigation of Roudab plain, Sabzevar, Khorasan Razavi province. Roudab plain encloses an area of approximately 392 km2 . Most of the groundwater is intended for supplementing agricultural water demand. This study strives for zoning ground water quality and qualification for drip and sprinkler irrigation with the aid of GIS. Results of water quality zoning in agricultural sector based on Wilcox classification showed that the groundwater of this region falls into intermediate (54%) and unsuitable water classes (46%). Also, 39% of groundwater has little impact on soil permeability, however, in terms of EC (60%) and TDS (56%), groundwater application impose severe limitations for irrigation. In the case of zoning drip and sprinkler irrigation suitability levels of acidity, chlorine and total dissolved solids (TDS) were23 and 86, respectively. Besides, 53% of the area exceed permissible levels, while total area by sprinkler irrigation application will have suitable level of acidity while impermissible concentrations of sodium and chlorine.