Effect of Treated Wastewater and Irrigation Systems
 on Soil Chemical and Physical Properties in an Arid Region

M. Afyuni, J. Abedi & M.R. Baghri

College of Agriculture, Isfahan University of Technology, Isfahan, Iran
e-mail: Afyuni@cc.iut.ac.ir

Abstract

In the arid and semiarid regions wastewater reclamation and reuse has become an important element in the water-resource planning. This is because the scarcity of fresh water is increasing, there is high nutrient concentration in wastewater -- which is of interest as the cost of chemical fertilizers is high, the cost of needed treatment to convert wastewater in to forms suitable for other applications is high, and the wastewater is generally available aplenty near the agricultural lands.  The agricultural lands around the wastewater treatment plants in Isfahan, Iran are irrigated using the secondary treated wastewater. The objective of this study was to determine the suitability of the treated wastewater for irrigation in order to have better management of irrigation systems for higher crop production.  A two-year field experiment was conducted with two types of water -- wastewater and groundwater, used by sprinkler and surface irrigation systems for producing sugar beet, corn and sunflower. Soil samples were taken to 120 cm depth to determine the concentration of heavy metals such as Pb, Mn, Co, Cu, Fe, Cd, and Ni. Irrigation system had no significant effect on extractable metal concentrations in the soil profile. The accumulation of the metals in the surface soil was significantly higher in the wastewater treated plots as compared to the plots receiving groundwater. The irrigation system had a significant effect on infiltration rate, bulk density and total porosity. Under sprinkler irrigation system the infiltration rate increased significantly.