The effects of treated wastewater on soil chemical properties using subsurface and surface irrigation methods

The increasing need for water in the arid areas of the world has resulted in the emergence of wastewater application for agriculture and landscape. The effects of wastewater on soil chemical properties using two irrigation methods (subsurface irrigation with porous pipe and surface irrigation) were investigated in 2005 at Mahmoudabad research centre located at Isfahan, in central Iran. Soil samples were collected from depths of 0–15, 15–30 and 30–60 cm and were analyzed for salt content (EC), soluble sodium (Na), soluble calcium (Ca), soluble magnesium (Mg), total nitrogen (TN), phosphorus (P) and potassium (K). The soil EC, Na and Mg of the first layer of soil (0–15 cm) were significantly greater with subsurface irrigation than with surface irrigation. The EC, Ca and Mg of second and third soil layers irrigated with wastewater were less as compared with groundwater. The amount of K in the first and second soil layers irrigated with wastewater was significantly greater than those irrigated with groundwater. There was no significant effect on soil Na, P and TN due to irrigation with wastewater.