Field experiments were carried out to study the effect of some farmimplements traffic on the state of soil compaction in terms of soil bulk density and soil penetration resistance. Two main experiments were carried out. The first experiment was conducted during land levelling operation for rice using three different tractors equipped with three different land levellers at four different forward speeds and two different moisture contents. The second experiment was conducted during   harvesting rice using three different combines at four different forward speeds.
The experimental results revealed the following points:
1. Penetration resistance as well as soil bulk density values was higher for heavy tractors and heavy agricultural machines than for light ones under all investigated parameters.
2. The root growth zone (20 cm depth) and crop yield were in the safe region under the following conditions.

In the case of using heavy tractor at forward speed of less than 3.6 km/h, and moisture content of about 15%.
In the case of using medium tractor at forward speed of less than 4.2 km/h, and moisture content ranged between 15 - 25%.
In the case of using light tractor  at forward speed of less than 5.8 km/h, and moisture content of about 25%.
In the case of using the combine harvesters  at forward speed of about3.3 km/h.