Wastewater effects on some soil physical and chemical properties in rangeland restoration projects (Case study: East Isfahan)

This study aimed to investigate the effects of urban wastewater on some soil physical and chemical properties in Segzi، East Isfahan. Six sites were selected considering the planted species (Haloxylon persicum and Nitraria schoberi) and irrigation types (control or no irrigation، water logged and furrow irrigation methods). The 4 to 12 replications were chosen in each site depending on its'' size. Soil samples were collected in all replications from the 0‒10 and 10‒30 cm layers. Soil properties such as texture، organic matter، acidity، electrical conductivity، total soluble sodium، calcium and magnesium concentrations، and structural stability (dispersible clay) were measured for 94 collected soil samples. One-way ANOVA، Duncan''s mean test and Principal Component Analysis were used to analyze and interpret the data. The results showed that wastewater affected some soil properties by leaching soluble salts into deeper soil horizons and also adding organic matter and some minerals into the soil. Electrical conductivities of the 0‒10 cm layer in control sites (no irrigation) and the 10‒30 cm layer in sites with furrow irrigation method were significantly greater than water-logged irrigated sites (α= 0. 05). Applying wastewater increased soil organic matter content and aggregate stability significantly (α= 0. 05). Irrigating the sites with wastewater decreased soluble sodium contents and dispersible clay of the soil surfaces; hence the soil structural stability was increased. Overall، applying wastewater to irrigate the planted seedlings in rangeland restoration projects has benefits as its use in these areas has lower environmental risk when compared with agricultural fields.