A tool for injecting solid fertilizer spikes into soil for tree and plant root nutrition utilizing elongated brackets to reduce the step-up height, form a fertilizer load chamber and to provide for a spring fertilizer spike retention mechanism such that the tool is fully operable in an upright position wherein a fertilizer spike is left embedded in the ground and detached from the tool without the need to remove the tool from the ground in a manner where, with one process of downward movement of the foot bar, two functions occur simultaneously, namely; the full injection of the fertilizer spike into the soil concurrent with the full release of the fertilizer spike from the tool by the complete ejection of the fertilizer spike from the fertilizer spike load chamber and the spring fertilizer spike retention mechanism. The tool is also provided with a spring wire that is adapted such that the fertilizer spike chamber, the injector tube and the foot bar are held in place in the load position until released by downward force by the operator on the top the foot bar.