The effects of treated wastewater on soil chemical properties using subsurface and surface irrigation methods M. Heidarpour *, B. Mostafazadeh-Fard 1 , J. Abedi Koupai 2 , R. Malekian 3 Department of Water Engineering, Isfahan University of Technology, Isfahan, Iran 1. Introduction Water is a scarce commodity in the Middle East and North Africa (MENA) and its availability is declining to a crisis level. According to the World Bank (1996), MENA is the driest region in the world with only 1% of the world’s freshwater resources. The reuse of wastewaters for purposes such as agricultural irrigation reduces the amount of water that needs to be extracted from environmental water sources (USEPA, 1992; Gregory, 2000). Wastewater is the only potential water source, which will increase as the population grows and the demand on freshwater increases. The benefits from using different types of recycled water and current knowledge and opinions relating to risks such as water quality issues are discussed by Toze (2006). The use of non-conventional water resources and opportunities for achieving food security in water-scarce countries are presented in Qadir et al. (2007). An overview of existing urban wastewater disposal infrastructure, waste- water agriculture practices and the quality of water used, the health implications and the level of institutional awareness of wastewater related issues in the Kathmandu Valley are presented by Rutkowski et al. (2006). There is potential for inorganic nutrients present in recycled water to be used as a fertilizer source. Soil microorganisms have been observed to increase metabolic activity when sewage effluent is used for irrigation (Meli et al., agricultural water management 90 (2007) 87–94 article info Article history: Accepted 14 February 2007 Published on line 26 March 2007 Keywords: Reuse Effluent Porous pipe Subsurface trickle irrigation Soil minerals movement Bermudagrass abstract 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. # 2007 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +98 311 391 3436; fax: +98 311 391 2254. E-mail addresses: heidar@cc.iut.ac.ir (M. Heidarpour), behrouz@cc.iut.ac.ir (B. Mostafazadeh-Fard), koupai@cc.iut.ac.ir (J. Abedi Koupai), ramalekian@yahoo.com (R. Malekian). 1 Tel.: +98 311 391 3430; fax: +98 311 391 2254. 2 Tel.: +98 311 391 3433; fax: +98 311 391 2254. 3 Fax: +98 311 391 2254. available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/agwat 0378-3774/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.agwat.2007.02.009