Fertilizer selector for formula fertilization

The invention discloses a fertilizer selector for formula fertilization. The fertilizer selector comprises control command guide pipes, control valves, normal close three-way hydraulic valves and fertilizer tanks; the control valves are connected with a water supply pipeline, and is communicated with a control port of each normal close three-way hydraulic valve through the corresponding control command guide pipe to form a control part of the fertilizer selector; a fertilizer inlet of each normal close three-way hydraulic valve is communicated with the corresponding fertilizer tank, and a hydraulic valve outlet is communicated with a fertilizer injector, so that an execution part of the fertilizer selector is formed; and the quantity of the hydraulic valves is as the same as the component quantity of a fertilizer stored in each fertilizer tank. After the fertilizer selector disclosed by the invention is used, a normal close three-way hydraulic valve principle is used, the hydraulic valves are connected with the fertilizer tanks and the water supply pipeline to form a fertilization device, the hydraulic valve is taken as a control switch at the same time to control the select of the type and the quantity of fertilizer components to carry out the exact formula fertilization, so that various fertilizer combination modes can be realized; and the conventional fertilizer injector with high price can be replaced, the range of the practical application of a water fertilizer machine can be enlarged, the fertilizer selector can be taken as a component to be loaded on any water fertilizer machine, and the water fertilizer machine can be sufficiently and effectively used.