Two field experiments were carried out during 1990and 1991 seasons at the Agricultural Research and Experiment Center of the Faculty of Agriculture Moshtohor to study the effect of different tillage systems including chisel plowing alone and in combination with subsoiling or moldboard plowing N fertilisation levels (zero. 30 and 60 kg/fed.) with and without soybean seed inoculation on yield, and its components of soybean, associated weeds and some soil properties. Results could be summarized as follows The combination treatment (moldboarding + chisel plowing) reduced the bulk density whereas, porositiv percentage of the soil increased The lowest salinity value was recorded with subsoiling + chisel plowing. Moldboarding + chisel plowing followed bv subsoiling + chisel plowing were good procedures to depress weeds in soybean Increasing nitrogen levels significantly decreased fresh and dry weights at 45 days from planting and at harvest. All tillage treatments increased root surface area (RSA) of soybean as compared with control (no-till) RSA significantly increased by increasing nitrogen levels and inoculation with Rizobium japonicum The highest values of seed yield of soybean and its components (number of pods/ plant, seed yield / plant and 100-secd weight) as well as plant height and number of branches/ plant were recorded with moldboarding + chisel plowing. Increasing nitrogen levels significantly increasing seed yield and yield components of soybean The maximum seed yield was recorded by applying 60 kg N/ fed. Inoculation significantly increased seed yield of soybean. Also. inoculation gave the best results in number of pods/ plant number of seeds/ pod and weight of seed/ plant. Moldboarding + chisel plowing x inoculation x 60 N was the best interaction in depressing weed at 45 days from planting and at harvest The highest yield was obtained from the moldboarding + chisel plowing x inoculation x 60 N interaction.