1. Polyvalent sowing machine adapted to be used both for seeding large surfaces for corps and micro-plots of plantations for experimentation and comprising a mobile frame on which is mounted at least one sowing element of the type comprising a vertical sowing disc (8), perforated on its periphery and rotating inside an enclosure which it divides into two compartments of which one (7) constitutes a reserves of seeds to be sown and the other (15) is connected to a source of suction (16), so that said seeds are taken by suction one by one through the perforations (1) of the disc (8) to be transported to a location away from suction of the stroke of the disc (8) where they are released with a view to be sown, said sowing machine comprising a device for recovery by depression of excess seeds comprising a reservoir (18) for receiving the excess seeds capable of being placed in vacuo and connected by an extraction pipe (4) to said compartment (7) constituting the reserve of seeds to be sown and further comprising two mobile trap doors (5, 12) of which one (12) is interposed between a seed supply hopper (19) and said compartment (7) constituting reserve of seeds and serves to open or close said supply hopper (19), characterized in that the other mobile trap door (5) serves to open or close said seed extraction pipe (4) and in that this extraction pipe (4) connects to said reservoir (18) for receiving the excess seeds the lower part of that of said compartments (7) forming seed reserve.
