The Effect of Compaction on the Physical and Hydrodynamic Properties of Soil and on the Growth and Productivity of Soybean Crop

The research was conducted at the Scientific and Agricultural Research Center in Latakia ( Sitkheris Center)in the year of 2022 using Randomized Complete Block Design at which four different levels of pressure were applied to a silty clay soil (0- 163- 216- 297 kpa)at the plastic limit (the optimal tillage limit of the soil). Results showed that soil compaction in the surface layer (5-20 cm) caused an increase in the bulk density by 0.21 g/cm3 at the pressure 163 kpa ,an increase by 0.25 g/cm3 at the pressure 216 kpa and an increase by 0.33 g/cm3 at the pressure 297 kpa. This effect diminished as depth increased, and the total prose size significantly decreased at all levels of the applied pressure compared to the control treatment. A significant decrease, was also noticed in the leaf surface area of the soybean (flowering stage) along with the decrease in the pressure, where the decrease ranged from 4329.93 cm2/plant, in the treatment without pressure, to 1746.22 cm2/plant at the pressure 297 kpa. The results also showed a decline in the soybean productivity and the percentage of both protein and oil in the dry seeds along with the increase in the pressure, where the productivity recorded a decline by 214.22 kg/dunum at the pressure 297 kpa compared to the control treatment.