Abstract: Product dosing system for agricultural machines, in particular for fertilizer distributors such that the simple salts carrying nutrients, that is to say, nitrogen, potassium and phosphorus, can be arranged in granulated form in respective deposit hoppers aligned in the advance direction of the fertilizing machine to directly distribute the single fertilizer to the soil to be fertilized, as well as having an auger 8 for regulating the single fertilizer for its conduction towards collection and distribution dosing means, thus, having an auger for regulating the doses of single fertilizer in granulated form and dosing means for each of the hoppers, allowing the regulation and measurement speed to depend on the advance speed of the machine, the machine having to that end a ground engaging member through which the movement is transmitted to the regulating augers and to the axles of the collection and distribution dosing machines.