Accurate variable-rate fertilizing device

The utility model relates to a precise variable fertilizing device which mainly comprises a fertilizer box, a supporting plate, a fertilizer discharging shaft, a stepping motor, a worm and gear speed reducer, a diaphragm type coupler, a guide rail, an electric push rod, a movable connecting plate, a sliding block, a fertilizer discharging box, a bidirectional thrust ball bearing and a fertilizer discharging grooved wheel. Wherein an output shaft of the stepping motor is fixedly connected to the input end of the worm gear reducer through a flat key, the output shaft end of the worm gear reducer is fixed to the left side of the diaphragm coupling, the right side of the diaphragm coupling is fixedly connected to the left end of the fertilizer discharging shaft, the right end of the fertilizer discharging shaft horizontally penetrates through the supporting plate, and the supporting plate is fixedly connected with the fertilizer box; a fertilizer feeding grooved wheel is connected to the fertilizer feeding shaft