Soil and water salinity is a significant factor resulting in land degradation and reduced productivity particularly in arid and semi-arid regions of the world. Therefore, reclamation of salt-affected soils is necessary to achieve sustainable production of agricultural produces. In the present study, the first, various soil conditioners were synthesized in order to improve chemical and physical characteristics of saline-sodic soils. In the next step, the efficacy of the synthesized conditioners in improving soil characteristics and seed germination and initial growth of corn ( Zea mays L. ) was evaluated. Among different formulations tested in the preliminary tests, three formulations were selected to synthesize soil conditioners. Sodium polyphosphate, as a chelating agent, sodium lignosulphonate as a reclamator of soil physical characteristics conditioner, ethylene glycol as a surfactant, urea, and potassium sulphate as plant nutrient sources were used in the synthesis of soil conditioners. Three soil conditioners differed in the ratio of H 2 SO 4 to citric acid (0:9, 3:6, and 3:3 w:w in compositions 1, 2 and 3, respectively) were used for buffering soil pH. In the second part, the efficacy of soil conditioners in improving physical (i.e., hydraulic conductivity, water dispersible clay, available water, and penetration resistance) and chemical characteristics (i.e., pH, EC, SAR, and OC) of a saline-sodic soil was tested. Three soil conditioners were applied at four application rates (0, 10, 20, and 30 L ha 1- ). Leaching of soil columns was performed at 4 stages. Results showed that soil conditioners significantly improved physicochemical characteristics of the studied soil. Compositions 1 and 2 significantly reduced soil pH in comparison with the control treatment. All three conditioners largely reduced EC, SAR, and ESP in comparison with the initial soil. Application of composition 2, at 10 and 20 L ha -1 rates resulted in significant reduction of dispersible clay percentage. All three soil conditioner compositions increased plant available water in soil. Soil penetration resistance was also smaller in the soil columns treated with compostions 1 and 2 at applied rates of 10 and 20 L ha -1 . The most effective treatments in improving soil conditions were selected using cluster analysis for plant cultivation test. Composition 1 at 10 L ha -1 and composition 2 at the rates of 10 and 20 L ha -1 were chosen and their effect on seed germination and initial growth of corn ( Zea mays L.) was investigated in the same saline-sodic soil. Seed germination rate, root and shoot dry mass and relative water content of corn plants were higher in the soils treated with soil conditioners in comparison with those in the untreated soil. According to the results obtained, soil conditioner compositions 1 and 2 at applied rates of 10 and 20 L ha -1 might be recommended for improving physical properties of saline-sodic soils; although further studies particularly at the field scale are needed. Keywords : Available water, Hydraulic conductivity, Leaching, Salt-affected soils, Sodium Adsorbtion Ratio, Soil conditioners