This study were carried out to evaluate the effect of irrigation by treated wastewater (TWW) on some chemical properties of cultivated lacustrine and calcareous soils, the growth and macronutrients contents of soybean (Glycine max L.), corn (Zea mays L.) faba bean (Vicia faba) and wheat (Triticum aestivum L.) plants and the chemical composition of drainage water. Pot experiments were carried out in the greenhouse at the Agriculture Research Farm, Faculty of Agriculture, Alexandria University. Fifty kgs soil were placed in a plastic pot and the seeds of each plant species were sown and irrigated by freshwater (FW) for two weeks then by the tested water treatments: FW, TWW or 1:1 FW/TWW. Soil and plant samples were collected two weeks before plant harvest for analysis and samples of drainage water were collected for the determination of pH, TDS, NO3- and total P.
The results showed significant increases in the ECe, OM and available N, P and K in soils as a result of TWW and 1:1 FW/TWW irrigation. Also, the concentrations of N, P and K in leaves of plants irrigated by TWW and 1:1 FW/TWW were significantly higher than in those irrigated by FW. In addition, the dry weights of plants were significantly higher as a result of irrigation by TWW and 1:1 FW/TWW than of those irrigated by FW.
The drainage waters of the cultivated soils irrigated by TWW and 1:1 FW/TWW had higher concentrations of TDS, NO3- and total P than of those irrigated by FW. The concentrations of TDS in drainage waters from cultivated calcareous soils were almost higher than of those from cultivated lacustrine soils. The results obtained proved that the beneficial effects of irrigation by treated wastewater were relatively more found with calcareous soil than with lacustrine soil.