Effect of Seed Priming and Biofertilization Treatments on Vegetative Growth Characters of Soybean under Water Stress Conditions

Two field experiments were conducted at the experimental farm, Faculty of Agriculture, Mansoura University, Dakahlia Governorate, Egypt during 2022 and 2023 seasons to improving growth of soybean plants using seed priming (without, hydropriming, calcium chloride, humic acid and seaweed extract) and biofertilization (without, inoculation with Rhizobium japonicum, Mycorrhiza and Rhizobium japonicum + Mycorrhiza) treatments under water stress conditions (irrigation levels as 100, 80 and 60 as a ratio from water requirement). Every irrigation level was tested independently. Each irrigation level experiment was conducted in three replications using a strip-plot design. The highest values of all examined growth parameters were obtained in both seasons when water stress treatment was not applied, i.e., when irrigation level was set at 100% of water need (2818 m3/fed). The highest values of all the development characteristics under study were obtained in both seasons when seeds were primed in calcium chloride (CaCl2) at a rate of 6 g/L. Seed inoculation with Rhizobium japonicum besides Mycorrhiza exceeded other biofertilization treatments and produced the highest values of all studied growth characters in both seasons. In order to save irrigation water at the same time maintaining highest growth parameters, it could be recommended that irrigation soybean plants at the level of 80 % from water requirement (2254.4 m3/fed) and priming seed in CaCl2 at 6 g/L besides inoculation seeds with Rhizobium japonicum in addition inoculation with Mycorrhiza under the local climate of Egypt's Dakahlia Governorate's Mansoura district.