The Effects of Different Water Qualities and Irrigation Methods on Soil Chemical Properties

In this study, the effects of irrigation methods (surface drip and subsurface drip) and water qualities (municipal treated effluent and fresh water) with irrigation scheduling based on soil moisture and root depth monitoring were evaluated on the chemical properties of the soil. A split plot experiment with two main treatments (irrigation methods) and two sub-main treatments (irrigation water qualities) with four replications were designed and executed in Koshkak research centre (Southern Iran). Soil samples were collected from depths of 0-20, 20-40 and 40-60 cm and were analyzed for electrical conductivity (EC), soluble sodium (Na) and chloride (Cl) concentrations, total nitrogen (TN) and phosphorus (P). Results showed that the soil EC, Na and Cl of the second and third layers of soil were significantly greater with surface irrigation than with subsurface irrigation. The EC, Na and Cl of second and third soil layers irrigated with wastewater were higher as compared with groundwater. The soil EC, Na and Cl content increased with increasing the depth of the soil layer. The fluctuations in nitrogen concentration were opposite to the fluctuations in Cl concentration as the nitrogen content of the soil decreased with increasing the soil depth. The best water saving and water productivity was obtained with sub-surface drip irrigation.