On-line instant proportioning fertilizer mixing device and fertilizer mixing method for multiple liquid fertilizers

The invention provides an on-line instant proportioning fertilizer mixing device and a fertilizer mixing method for multiple liquid fertilizers, and belongs to the field of intelligent agricultural machinery. The problems of high labor intensity, high harm to human bodies and poor mixing precision due to the fact that the mixing of the liquid fertilizer is mainly completed manually by an operator at present are solved. The device comprises a plurality of fertilizer outlet mechanisms, a liquid fertilizer injector and a controller, each fertilizer outlet mechanism comprises a liquid fertilizer box and a main pipeline, a fertilizer outlet of the liquid fertilizer box is connected with the liquid fertilizer injector through the main pipeline, the main pipeline is sequentially provided with a liquid pump and a flow sensor in the flowing direction of the fertilizer, and the liquid pump is connected with the liquid fertilizer injector through the main pipeline. A proportional overflow valve is arranged between the o