How do you fertilize trees via liquid injection?

Answer 1

It is by getting the dissolved nutrients directly inside the tree's circulatory system that trees are fertilized by liquid injection.

Specifically, trees naturally accept dissolved nutrients through the roots. From the roots, the nutrients circulate throughout the above ground body parts by way of the up-flowing channel called the xylem. Liquid injections may be made indirectly through the surrounding soil or directly through root or tree injectors.