I have learned over the years of trying to grow maples in really heavy sticky clay to create a good drainage system.
I now try to get a planting position where I have the facility of adding large gravel to the base of the planting hole (having dug out and disposed of a barrow load of blue clay, and the ability of being able to dig a small trench away from the bottom of that hole to lower ground.
I then fill a piece of downspout with stones and feed it away from the base of the stones, and pack around it with more stones before planting and adding garden soil amended with a good leaf mould and a little slow release fertiliser.
I also sink another piece of downspout beside the planting hole to enable watering to the base of the roots for at least the first year of growth. I then plant the tree slightly high in the ground and mound up the soil around the base (this helps drainage tremendously and I would recommend it to anybody). I also avoid planting in too deep a shade position.
Japanese maples require a CONSTANT source of moisture. If you allow the soil to dry out, then soak the plant, allow it to dry out again and soak again etc you will create a stress situation for the plant and probably kill it.
Apparently these plants do NOT require a lot of fertiliser, as this is inclined to make them 'leggy'. I never fertilise mine.
The only exception would be a maple in a pot which I would assume would need a little fertiliser now and again to enrich the limited soil available in this situation.
Hints on Planting Japanese Maples