The great versatility of rotary power harrows which is the best in field preparing machines technologically is its soil mixing by the motion of a mixer. Snce the soil is not displacedupside-down, there is no loss of moisture and since the knives work vertically, a base will not be generated under the soil. This is the best machine to prepare fields for all planting applications. One can manage two works simultaneously by fitting different equipments on the rear mile at the back of the machine shift. One can press the soil worked before, by means of the roller at the back of the machine and the humidity of the soil doesnt go out. by means of the shaft with the safety system on the machine, any damage to the tractor or to the machine because of stones or roots is prevented.